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

This reverts commit f4284b4e.

This reverts commit efbe327f, reversing
changes made to 6d9bcd07.

We have contexts.hash_id which is enough (computed by postgres as a
trigger).

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.

Based on the suggestions in
https://kodimensional.dev/space-leak

This turned out to be quite heavy because of module import cycles.