New API for 10.3: trashbin api via webdav endpoint

[DeepDiver1975]

What Needs to be Documented?

refs owncloud/core#35716

10.3 will come with a new api on webdav for accessing the trashbin - including restore operations and permanent delete.

Details on the API can be found here owncloud/core#35636

Where Does This Need To Be Documented?

Server API/WebDAV

What Type Of Content Change Is This? (Optional)

• New Content Addition
• Old Content Deprecation
• Existing Content Simplification
• Bug Fix to Existing Content

Which Manual Does This Relate To? (Optional)

Where ever all WebDAV APIs are documented

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

[settermjd]

Successfully tested all functionality and am working through documenting the API endpoints.