Redesign Box Clock around named layouts and a full web customizer

[stweedo]

This redesigns Box Clock around named layouts and a full web customizer.

Changes

• add a web customizer for Box Clock
• add a live watch-face preview
• support drag editing in the customizer
• support box resize and boundary editing
• add undo/redo for preview edits
• add layout create, duplicate, rename, and delete actions
• switch from the old numbered config flow to named layout configs
• split app state into settings plus per-layout config files
• keep on-watch drag-to-position editing
• simplify the on-watch settings menu
• add custom background upload support
• support clockbg, solid, and image backgrounds
• add modular PBF font support
• update the runtime app to use the new config model
• remove the old global Graphics patching approach
• fix startup on newer firmware
• refresh the bundled example layouts
• refresh the screenshots
• update the README
• update metadata and changelog

[bobrippling]

Wow that's a lot of interface.html. I'm gonna be honest, I read the JS but I only skimmed the interface. I know you're a keen bangle dev so my assumption is the interface is tested too :) Thanks!

[stweedo]

Thanks for merging! I had over 100 commits on the dev branch for this and tested it each time along the way. It should be relatively stable and bug free, but I'm sure there are edge cases I haven't encountered yet. I may try to slim it up some, and I also want to add clock info support but when I tested that it was too slow for some reason. Thanks again for checking it over.

[bobrippling]

I can believe it! Not a problem, cheers again for the app improvements as well