inveniomanage: `config update` initial port

* Addresses problem with running `inveniomanage` commands from
  `inveniocfg --update-all`.

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
BibFormat: bfe elements loader inside engine

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>