Add an owl container for PODD ontologies

[alexandremairin]

Exemple : http://ecoinformatics.org/oboe/oboe.1.0/oboe.owl

[ansell]

OWL container here is basically a parent ontology that imports all of the latest versions.

Before implementing this we would need to make it work with the current getPermanentRepository algorithm that expects the full set of ontologies to exactly match, which may not happen if the parent was not chosen by everyone.