Add term-metadata schema to COB

[matentzn]

Right now, anyone can add any new annotation properties to COB. We should:

1. Have an explicit SOP for this, and not just led anyone decide that by themselves

2. Have a super strict metadata schema for COB terms that we will always adhere to:

3. Always have a definition

4. Always have a dcterms:creator

5. Always have a creation date

6. Always have an issue tracker item

EDIT: removed dc:date to not detract as to the point of this issue.

[wdduncan]

When did we decide on dc:date? I thought we were supposed to use oboInOWL:creation_date.

[matentzn]

We use neither in COB right now afaiks, but I strongly favour the death of oboInOwl for most use cases: information-artifact-ontology/ontology-metadata#63 in any case, this is not what I meant to discuss here, I remove the date (just saw @ddooley adding that here #232)

[wdduncan]

I strongly favor the death of oboInOwl for most use cases

Hah! I have no strong preference for either dc:date or oboInOWL:creation_date. We just need to decide on one.