Add new tokens command for managing API tokens

[cmoog]

$ coder tokens
Create and manage API Tokens for authenticating the CLI.
Statically authenticate using the token value with the `CODER_TOKEN` and `CODER_URL` environment variables.

Usage:
  coder tokens [command]

Available Commands:
  create      create generates a new API token and prints it to stdout
  ls          show the user's active API tokens
  regen       regenerate an API token by its unique ID and print the new token to stdout
  rm          remove an API token by its unique ID

Flags:
  -h, --help   help for tokens

Global Flags:
  -v, --verbose   show verbose output

Use "coder tokens [command] --help" for more information about a command.

[cmoog]

This will require a very pointed help desk article showing how the CLI can be authenticated for CI.

[cmoog]

As shown in the integration tests, this is currently blocked by https://github.com/cdr/c/pull/5891

[cmoog]

Merging as hidden until the permissions issue is resolved for coder tokens ls