Rewrite Timeline View to improve performance

[Airyzz]

TODO:

• [x] url preview widgets
• [x] message timestamps
• [x] date seperators
• [x] failed to decrypt messages
• [x] jump to latest button
• [x] read receipts
• [x] handle url preview failure
• [x] handle read receipt when new event received and is attached to bottom

[Airyzz]

Closes #161

[Airyzz]

Closes #246 as the code this error was throwing from no longer exists