Documentation for each server/cloud provider

[tobixen]

Perhaps a separate document, with one section for every server/cloud provider, including ...

• Links to the relevant issues here on the github tracker.
• Caveats, like parts of the standard that is not supported
• What CalDAV-URL to use
• Typical format for calendar URLs and principal URLs.

[tobixen]

One section with compatibility issues and one section on caldav URLs in the doc. I still think it may be a good idea with one section per caldav server, perhaps.