Transmit kubernetes tokens using juju secrets

[addyess]

Overview

• Introduce a new schema for kube-control which provides auth tokens through juju secrets
• Charm upgrades will handle migrations to juju secrets in any order of unit upgrades
• Introduce sharing the ca-certificate of the k8s endpoint via this relation

Details

• leverages juju secrets to set ca-certificates and auth tokens
• Requirer charms must be rebuilt to take advantage of the new v1 schema
  • this was intentional to make the library more backwards compatible
  • new libraries SUPPORT v1, but the charm must instruct the library to use it
  • new requirers talking to old providers will still function
• Provider charms after rebuild will natively take advantage of v1 schema when provider requests it

[mateoflorido]

LGTM! I have a couple of comments and suggestions, feel free to disregard if they’re not relevant

[mateoflorido]

Nice, thanks for setting it as a secret

[mateoflorido]

If we set this to "", it will still be parsed into the dict and json representation. If that's okay, we can leave it as is. However, if we want to omit these values, we should set them to None instead

[addyess]

I'll document here why they must be filled with something

[mateoflorido]

LGTM. Thanks for adding a revoking mechanism.