Update the Phenopackets Documentation

Provide more values for the documentation for MoleculeContext https://github.com/ga4gh/phenopacket-schema/issues/334
Add details to the documentation about the MedicalAction field. https://github.com/ga4gh/phenopacket-schema/issues/347
Avoid the term 'germline sample' outside the context of cancer https://github.com/ga4gh/phenopacket-schema/issues/325
One-sided ReferenceRange: remove permissions to include invalid numbers such as NaNs and infinities. https://github.com/ga4gh/phenopacket-schema/issues/343
Serialize numbers as a string. https://github.com/ga4gh/phenopacket-schema/issues/340
Update/add (?) Requirements on version strings in documentation https://github.com/ga4gh/phenopacket-schema/issues/288

Start by reviewing the six linked issues and locating the documentation covering MoleculeContext, MedicalAction, germline samples, ReferenceRange, number serialization, and version strings. Done means each requested documentation or requirement update is addressed and the affected documentation is internally consistent.

Written by the indexing model from the issue text.