Also add a comment on `AuthResult` type to explain that
we can also access the claims in the db using GUCs.
Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>
Closes https://github.com/PostgREST/postgrest/issues/4226.
This requires moving query generation to the top App.hs module.
At this point is also simple to log the transaction variables + the
pre-request function call but this is not done here to reduce scope.
