Support creating docker and kubernetes credentials for Container Registry

[F21]

Is your feature request related to a problem? Please describe.
I would like to be able to create docker and kubernetes credentials to access the container registry.

Describe the solution you'd like
Implement docker and kubernetes container registry resources.

Describe alternatives you've considered
n/a

Additional context
APIs

• https://www.vultr.com/api/#tag/Container-Registry/operation/create-registry-docker-credentials
• https://www.vultr.com/api/#tag/Container-Registry/operation/create-registry-kubernetes-docker-credentials