improve integration with OWL-Time

This reduces one level of indirection and duplication in the vocab. We can simply consider any Intent, Commitment and EconomicEvent as more specific time:TemporalEntity and use properties defined in Time Ontology in OWL directly one them. Since we already have distinct Intent, Commitment and EconomicEvent we don't need in addition observed*, commited* and intended* prefixes. One can simply check rdf:type (@type) of flow to have that knowledge.

Our examples already incorrectly use time:intervalEnds and time:intervalStarts (which have time:ProperInterval as range) we have to update them to time:hasBeggining and time:hasEnd (which have time:Instant as range). If we accept this PR, we can use those properties directly on any flow or Process.