Add root term annotations

[cthoyt]

Related to https://github.com/OBOFoundry/OBOFoundry.github.io/issues/2149

What This PR Does

Applies the annotation property has ontology root term (IAO:0000700) in several ontologies in this repository, using each ontology's respective (obvious) root element. If desired, I could go and do the rest as well.

Why this is helpful

• the Ontology Lookup Service uses this to help better display ontologies
• if any of the terms mentioned above are ever aligned with an upper ontology like BFO, it still will be the thing shown on OLS as the "root"
• this will be generally useful for things like alignment with COB since it makes it easier to figure out what are the upper level terms in this ontology are

[cthoyt]

@fbastian can you please take a look at this?

[cthoyt]

@matentzn thanks