A way to handle namespaces

[mehmetc]

We need to way to handle multiple namespace within an ontology.
You could opt to split an ontology into smaller sub-ontologies(namespaces). Mostly because the entities make only sense in a specific context
For example:
Here is a core namespace. it holds entities that sub-ontologies(namespaces) could inherit from:
PREFIX odis: <https://data.odis.be/>
odis:Agent
odis:TypeAgent
...

Here are all the entities that belong to a Persoon entity
PREFIX odisp: <https://data.odis.be/#persoon/>
odisp:Persoon inherits from odis:Agent
odis:Diploma
odis:PolitiekMandaat

An approach could be to have a namespace registry.
Check if RDF::Vocabulary can be used

[mehmetc]

See also #78