feat(core): add cli attribute values crud

[jrschumacher]

No description provided.

[jakedoublev]

Changes I committed:

1. better error messages (though there's always still room for improvement)
2. metadata labels to attribute values create/update
3. more usage of proto message field accessor/getter methods (which I understand help avoid nil pointer panics)
4. bump to the latest sdk and gencode versions

I also added support for the update calls on attribute values to add/replace/remove members, but I believe members functionality has only been added platform-side on create of values with members, not update of existing values yet. We should probably comment it out to avoid confusion until it's been supported in the service.

[jakedoublev]

opentdf/platform#476 is open and referenced in the TODO with commented out members CLI subcommands

[jrschumacher]

Looks good to me!