- Re-enable orphan warnings that were manually disabled in many modules
- Remove non-Haskell files that were just sitting in the source tree
- Remove modules that were not called from anywhere
- Remove unused dependencies

This is not exhaustive by any means. In particular, some more weeding out
can be achieved by looking at individual functions and even branches of
functions. Weeder can help with that.

This contains only data, removes some Database dependency in imports.

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.

- DBCmd instead of Cmd
- remove FlowCmdM in favor of HasNodeStory

This fixes commit 5d5300cd which
automatically changed all 'return' to 'pure' in our code, resulting in
broken SQL etc.

Remove joins, use optionalRestrict instead.

Also, remove cabal.project because stack.yaml and package.yaml cover
dependencies already.