Add screen to configure Thunderbird Sync settings

[cketti]

This should include:

• a link to the web inferface to manage the account
• a button to "sync now"
• a way to change the device name
• an option to sign out
• a way to configure which data to sync (this would be the same or very similar to the post-sign-in screen from #8035)

This could look similar to this Firefox for Android screen: