JS: Add widget module

[jamisonderek]

What's new

• Add widget module. The widget module has a bunch of addXXX methods for adding frame, rframe, box, rbox, circle, disc, dot, glyph, icon, line, text and xbm images. Every time you call add, it returns an id that can be used by remove if you want to remove the item later. show() is non-blocking UI, so your JS can do other processing while the UI is displayed. The user can click the back button or you can call close() to dismiss the view.

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For the reviewer

• I've uploaded the firmware with this patch to a device and verified its functionality
• I've confirmed the bug to be fixed / feature to be stable

[Willy-JL]

Aside from that single nitpick, this is looking great, thank you so much! This will prove very useful for many scripts.

I can get that small change done tomorrow unless you do it before me 😄