possibility to use mf2:h-entry instead of as:Note

[elf-pavlik]

By adding @rhiaro work on https://github.com/rhiaro/mf2rdf to JSON-LD context, one could use mf2:h-entry instead of as:Note for result of as:Post / as:Create activity.

Another option to make as:Note more specific subtype of h-entry

as:Note rdfs:subClassOf mf2:h-entry .