Document behaviour when connection to server is not possible

[dkocher]

Depends on Online and Smart Synchronization connect mode

• Disconnect depending on error type in Online connect mode
• Pause of synchronization depending on error type in Smart Synchronization connect mode

Current implementation in Smart Synchronization connect mode

Error Type	Notification	Sync Paused	Error Badge	Remove Operation in Queue
Generic Server Error	✅	✖️	✅	✅
Network	✖️	✅	✖️	✖️
Authentication	✖️	✅	✖️	✖️
Quota	✅	✅	✖️	✖️