Improve OAuth Server
Currently, it allows to create new apps through the API and the code has been refactored (but it can be improved more but it is not a prority at this time).
- It will be interesting to have a UI to update and delete the installed apps.
- When the app boots, check and insert the default MoodleNet Local application.
- Make some test to verify it is working correctly
- Take a further look to https://aaronparecki.com/2018/07/07/7/oauth-for-the-open-web and rest of doc of https://gitlab.com/moodlenet/project/architecture/issues/2