This is safer than type Limit = Int

They are changed to MaybeFields ...Read instead when joining.

Remove joins, use optionalRestrict instead.

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

MR: gargantext/haskell-gargantext!53

This is because to_tsquery doesn't work with multiple words not
separated by AND or OR.

This reverts commit 29ee1972.

It introduces a bug, it should not be merged.

However, the code doesn't work currently.

This has couple of drawbacks:
- we use postgres-simple and a raw sql query, opaleye would be better
I guess
- there is a hack for empty query, this should be replaced by
removing the WHERE clause in this case

Limit, offset, search string, order by.