This allows subresources which belong to different API groups than
their parents to be registered in the APIInstaller and REST handlers
installed for them. The specific changes that makes this possible
are:
1. Allow subresource overrides to be specified while registering an
API group.
2. Use those overrides in the APIInstaller while validating the
resource/subresource group version to allow subresources which
belong to a different group to be registered if they have an
override specified.
3. Use the RESTMapper supplied in the override to map the REST paths
to the correct subresource storage object, i.e. correct group
version kinds.
Pass down into the server initialization the necessary interface for
handling client/server content type negotiation. Add integration tests
for the negotiation.
Remove Codec from versionInterfaces in meta (RESTMapper is now agnostic
to codec and serialization). Register api/latest.Codecs as the codec
factory and use latest.Codecs.LegacyCodec(version) as an equvialent to
the previous codec.
A NegotiatedSerializer is passed into the API installer (and
ParameterCodec, which abstracts conversion of query params) that can be
used to negotiate client/server request/response serialization. All
error paths are now negotiation aware, and are at least minimally
version aware.
Watch is specially coded to only allow application/json - a follow up
change will convert it to use negotiation.
Ensure the swagger scheme will include supported serializations - this
now includes application/yaml as a negotiated option.