Current API Key docs and API Key CLI docs mention application privileges and briefly the manage_ai_key cluster privilege, but they are not listed in Grant users access to secured resources, which summarizes all other privileges that are necessary.

We should add the privileges for the following use case:

Creating API Keys via the CLI tool requires

• manage_api_key privilege on cluster
• application privileges when the user creating the API Keys is not a superuser:

  applications:
    - application: 'apm'
      privileges: ['sourcemap:write', 'event:write', 'config_agent:read']
      resources: '*'

cc @bmorelli25