Add app auth config resource to tctl

[gabrielcorado]

Related to RFD 0030e.

Add app auth config resource commands subset (for CRUD) to tctl.

Manual testing

The new resource was tested with two Teleport cluster configurations: Standalone and Proxy + Auth server.

The testing used tctl to perform the CRUD operations of the resource:

version: v1
kind: app_auth_config
metadata:
  name: example
spec:
  app_labels:
  - name: teleport.internal/app-sub-kind
    values: [mcp]
  jwt:
    issuer: https://issuer
    audience: teleport
    jwks_url: https://issuer/.well-known/jwks.json

• tctl create appauth.yaml
• tctl create -f appauth.yaml
• tctl get appauthservers
• tctl edit app_auth_config/example
• tctl delete app_auth_config/example