Nextcloud 29 - 3.0.1 - Maintenance Update

This updates Splash to work with Nextcloud Hub 6 aka Nextcloud 28.

What did we do this time?

• Introduced compatibility with nextcloud 29
• Fix Login-Route (@Bl4DEx)
• Use Wikimedia as a default provider if the existing one is missing or none choosen

Known Issues:

• Preview does not always work