Unify streamer settings pages, add 'your city' settings

[dylmye]

Plan outline

• Move all streamer settings into one page - allow one streamer to be configured at a time
• Add 'your city' settings option - this will be used in a later feature to localise the homepage (limit top10 setlist query to city id)
• Add new state key: this will be the city ID and friendly name separated by a pipe
• No auto-locate because of stinky permissions