Split into Extract/Types/Utils modules.

Found some functions that are unused.

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.

FlowCmdM -> DBCmd or HasNodeStory is usually enough

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

This is safer than type Limit = Int

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

Read in backend works now, insert and upsert not yet.

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