Braille input: emulate keys outside text content and support combining input with modifiers (#7843)
* Use keyboard emulation for braille input when outside text controls. This allows backwards quick navigation using a capital sign. Support uncontracted partial translation outside text content
* Add toggling to braille input and allow creating keyboard input gestures from a name containing NVDA
* Basic support for combining modifiers with braille input
* Output error for unsupported input
* Integrated braille input modifiers in the key emulation system for BrailleDisplayGestures
* Added doc strings
* Support backward quick navigation for real this time
* Bind new toggle scripts to Eurobraille gestures