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 big commit improves the jobs API in a way that now we can
completely abstract away over a JobLog.

This works now for arbitrary nodes, irrespective of their type.