Based on work done in MDL-75650, this issue is scoped with adding the relevant oauth2service_moodlenet plugin. This will allow Moodle to use the resulting service for MoodleNet API calls in future issues.

You can see the other plugins in lib/oauth2/ for reference (once MDL-75650 is done)

This plugin should support the following

• OAuth 2 Authorization Server Metadata (aka discovery using this standard)
• Open* OAuth 2 Dynamic Client Registration
  • *This must use the 'open' configuration since:
    a) Moodle.net is the planned target and will have open registration for client apps.
    b) There isn't currently a means to support token-base registration in core Moodle. The issuer forms only permit registration via the "Base URL" field, and don't allow for tokens to be entered (yet - this may change in the OAuth 2 improvements in future)
• The plugin config should specify that it requires base URL (this is needed so that discovery, and then registration can take place) as well as indicate support for the above 2 features (discovery, registration)
• Template should contain the application URL 'https://moodle.net' (this can be changed)

User stories

This issue helps satisfy the following user stories:

1. As a site admin, I can configure MoodleNet sites as OAuth 2 services, so that the  services are available to me when configuring "share to MoodleNet" functionality in my LMS.
2. As a teacher, I can "connect" my LMS account to a MoodleNet account, so that it is authorised to share content to MoodleNet.

Note: This will satisfy 1, and is a part of satisfying 2 (since the auth code flow made by the teacher hasn't yet been implemented).

Completion criteria

• I can create a new MoodleNet OAuth 2 service via a button on the OAuth 2 services page
• Upon creation, the client_id and client_secret are provided to Moodle and saved
• Upon creation, the relevant OAuth 2 endpoints will be automatically discovered and populated
• No user field mappings are present after creation (this is not an identity service)