Changes needed for OAuth2 0.5.0

[mmattel]

WHAT Needs to be Documented?

All changes made that need documentation because of https://github.com/owncloud/oauth2/issues/299 (OAuth2 0.5.0)

WHERE Does This Need To Be Documented (Link)?

https://doc.owncloud.com/server/admin_manual/configuration/server/security/oauth2.html

WHY Should This Change Be Made?

App/code changes

(Optional) What Type Of Content Change Is This?

• [x] New Content Addition
• [ ] Old Content Deprecation
• [ ] Existing Content Simplification
• [ ] Bug Fix to Existing Content

(Optional) Which Manual Does This Relate To?

• [x] Admin Manual
• [ ] Developer Manual
• [ ] User Manual
• [ ] Android
• [ ] iOS
• [ ] Branded Clients
• [ ] Desktop Client
• [ ] Other

@pmaier1 @jnweiger fyi