Pre launch fixed and improvements

[adamrdrew]

• Fix left hand slide out menus in list on iOS (they all move to trash)
• Rename NoteContainer from NoteList header
• Fix NoteList header background color in dark mode to be the correct color
• If note title has never been set, set it from the first line of the content
• Make sure first run experience works correctly on all platforms, seems to run every time on iOS
• Remove Magic Chat from first run notification because it is currently disabled
• Keyboard extension for Markdown stuff?
• Make sure Markdown editor has focus when shown
• Make sure backlinks look good on iOS
• Make sure Backlink popover in iOS doesn't show up at weird times
• Swipe actions on folder and tag list for delete