This commit splits the policy checks we do on node operations into
"read" checks and "write" checks, so that we can enforce different kind
of policies based on the state of a node (i.e. published or not).

This commit refactors a bit the internal of the
`Gargantext.Database.Query.Tree` module so that it removes a lot of
repetitive boilerplate and paves the way to more interesting features.

It also:

* Adds the `isUserNode` boolean query
* Adjust source and target in publishNode and unpublishNode
* Pass the currently-logged-in user to tree API functions

Also, fixed breadcrumbs to accept AppRoute.

This allows us to have only one single (static) map which will be
treated by GHC as a CAF.

This commit introduces a new DB function called `isSharedWith`
that can be used to check for team/public/private nodes and their
shared resources.

This is a first stepping stone in avoiding bugs by having `UserId` and
`ContextId` being proper types, and not synonyms.

We also refactor things to have `AuthenticatedUser` carry the `UserId`.

Basically, Gargantext.Prelude exports all of Protolude now.

This commit partially undo the access policy checks for the
GraphQL endpoints, until we find a better story to correlate
the `user_id` we sometimes receive with the info from the
`AuthenticatedUser`.