(#22356) validate json schemas against the json meta-schema

The recently added json schema were not themselves being
validated.  And unfortunately, the json-schema gem doesn't
do any validation of the input schema, but rather is prone to
raising exceptions if the schema is invalid.

So add a spec test per-schema which validates the schema against
the meta-schema.

Also, fix up resource_type.json so that it is valid.
Merge pull request #1887 from kylog/issue/22356-add-json-meta-schema

(#22356) validate json schemas against the json meta-schema
Merge branch 'master' of https://github.com/puppetlabs/puppet