This gigantic commit ports the existing DB operations in GGTX to use the
transactional API, meaning that we can now compose DB operations and
they will all run in the same Postgres transaction using the same
connection, which will eliminate those class of bugs where concurrent DB
access might result in an inconsistent state.

On top of that, we simplify some parts of the API, for which a summary
is given below:

1. The `NodeStoryEnv` management has been greatly simplified; in the new
   API we don't need an external connection pool to be passed and we
   don't have to pass IO actions, we can just pass DB operations,
   therefore we can greatly simplify the API to just pass mostly pure
   values;

2. Due to the fact that our `DBTx` monad can't do arbitrary IO (which is
   a good thing) we cannot fire Central Exchange notifications
   immediately. Rather that happens now is that we collect the
   `CEMessage` to be sent and we fire them in the relevant concrete
   monad after we finished with the DB transaction. This means that in
   principle there would be a small delay between the DB operation
   taking place and the notification firing but in practice the latency
   should be negligible and bear in mind this is typically what we want:
   if we have a long DB Tx that triggers an error in the middle we don't
   want to be sending out CE messages prematurely if the overall
   operation didn't succeed!

3. There are still a few places in the codebase where we couldn't make
   things fully compositional with regards to the DBTx API, because we
   had Servant handlers which had DB operations mixed with other IO
   effectful computations (or other things like the notification from
   the `MonadJobStatus`). For now we are splitting these functions by
   manually running the partial DB operations, and while this is not
   ideal it can be fixed in subsequent merge requests.

4. The `WorkerEnv` doesn't use `IOException` as its `MonadError`
   anymore, as for consistency we can just use `BackendInternalError` by
   adding a `InternalWorkerError` data constructor accepting the
   `IOException` triggered by the Worker monad.

More testing is needed, with particular attention to performance
(regression) but this should hopefully offer a decent baseline.

commit b4755ad5
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Wed Jan 29 11:41:32 2025 +0100

    Code review, part II

    This commit splits the /export (renaming it to just remote) and tuck it
    under the /node hierarchy. The import also lives tucked in the /node.

commit 483bd3e5
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Tue Jan 28 09:34:14 2025 +0100

    Code review feedback

    * Rename `exampleS` into `exampleSchema`;
    * Revert commit about the public keys & co;

commit 18d207f0
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Tue Jan 28 09:50:56 2025 +0100

    Revert "Add _env_remote_transfer_keys field"

    This reverts commit 3ea32b50.

commit 9cc5159a
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Jan 20 10:00:53 2025 +0100

    Support transfering of notes

commit 1fe60d75
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Fri Jan 17 08:37:53 2025 +0100

    Refactor exporting and transfering of nodes

commit b39c1805
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Thu Jan 16 09:54:38 2025 +0100

    Preliminary work to transfer notes

commit b2f7a9a8
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Jan 13 15:25:34 2025 +0100

    Chunks the insertion of remote docs

commit 0d4e0554
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Jan 13 14:43:16 2025 +0100

    Move terms updating to separate job as well

commit c62480c7
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Jan 13 12:30:19 2025 +0100

    Proper support for importing documents

commit 6019587c
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Jan 6 15:44:13 2025 +0100

    Initial support for importing ngrams

commit 842b3d36
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Jan 6 15:07:21 2025 +0100

    Support exporting docs and ngrams (but not importing them yet)

commit 98708c2e
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Jan 6 12:32:17 2025 +0100

    Support exporting of tree hierarchies (with proviso)

    Exporting a corpus works, as it also exports its children, but for
    example the docs and terms nodes do not have any associated content.
    This is because those are stored in separate DB tables, and we need
    to find a way to export those as well.

commit c248eaf1
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Jan 6 11:50:14 2025 +0100

    Support trees of export nodes (to be tested)

commit dd2049aa
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Jan 6 11:23:30 2025 +0100

    Add getNodes function to Database.Query.Table.Node

commit c429cbb1
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Jan 6 10:39:37 2025 +0100

    Restrict export of nodes to only a few types

commit c648699e
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Jan 6 09:27:28 2025 +0100

    Update deps again (after rebase)

commit 7337820e
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Dec 16 16:07:49 2024 +0100

    Basic Remote API testing

commit 1eb59c52
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Dec 16 15:31:47 2024 +0100

    Barebone (non-streaming) storage of nodes

commit be5e9faf
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Dec 16 14:20:16 2024 +0100

    Send serialised nodes instead of dummy strings

commit aff15b60
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Dec 16 12:07:49 2024 +0100

    Remove redundant test imports

commit 6d776767
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Dec 16 12:01:55 2024 +0100

    Bolt-on ownership check for /remote/export

commit 58d9fcb0
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Dec 16 11:08:11 2024 +0100

    Proper error handling for remote import and export handlers

commit 23a06d28
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Dec 9 15:37:29 2024 +0100

    Update project deps

commit d5096e40
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Dec 2 17:05:04 2024 +0100

    Make a start on the remote (streaming) endpoints

    It typechecks but it exchange only a very simple string and
    it prints it.

commit 3ea32b50
Author: Alfredo Di Napoli <alfredo.dinapoli@gmail.com>
Date:   Mon Dec 2 11:26:11 2024 +0100

    Add _env_remote_transfer_keys field

    This adds a new randomly-generated pair of (PublicKey, PrivateKey) to be
    later used to send messages between instances.

    It also:

    * Returns a remote transfer pub key inside an AuthResponse
    * Adds pubKey roundtrip test