Update ontology service

[kilchenmann]

The ontology service contains the following new methods:

• [x] createOntology
• [x] deleteOntology
• [x] addResourceClass (to the ontology)
• [x] addProperty (to the resource class)
• [x] deleteResourceClass

And a few helper methods:

• [x] setCardinality
• [x] getOntologyName (from ontology IRI)
• [x] camelize (converts a string into camelcase notation; it's used to convert label into name)

This PR is a prototype / suggestion of ontology methods

[kilchenmann]

You should optimize the imports and keep commented code block only if it is relevant with explicit explanations (e.g. in ontology.service.ts: why keeping commented console.log? what are these GOAL code blocks?)

@flavens you're right. There's no reason for those comments. Thanks for the hint. I removed the comments

[kilchenmann]

Thanks @flavens