Support YAML format of LinkML

[yoavnash]

By supporting the YAML format of LinkML, we will get a lot of new capabilities for free. Plus, we benefit from the thought put into creating it.

Website: https://linkml.github.io/ Video and slides: https://yosemiteproject.org/linkml-a-linked-open-data-modeling-language/

[kysrpex]

It looks some kind of evolved version of our YAML. If it's a superset of what our YAML can do, then maybe yes, we should support it. It's a benefit for us, standardisation and the whole community.