feat(cpn): Jumper T20 support

[3djc]

This adds support for T20 model editing in Companion (no simulator)

Initial work by @pfeerick

This fixes #4233

[elecpower]

Compiler warnings that require attention:
/src/edgetx/companion/src/modeledit/flightmode.ui: Warning: The name 'verticalLayout_4' (QVBoxLayout) is already in use, defaulting to 'verticalLayout_41'.
/src/edgetx/companion/src/modeledit/flightmode.ui: Warning: The name 'verticalSpacer_2' (QSpacerItem) is already in use, defaulting to 'verticalSpacer_21'.
/src/edgetx/companion/src/modeledit/flightmode.ui: Warning: The name 'verticalLayout_5' (QVBoxLayout) is already in use, defaulting to 'verticalLayout_51'.
/src/edgetx/companion/src/modeledit/flightmode.ui: Warning: The name 'verticalSpacer' (QSpacerItem) is already in use, defaulting to 'verticalSpacer1'.

[pfeerick]

Might want to do something about this... firmware may also need some TLC also though, as Trm7/T7 & Trm8/T8 don't appear as an available mix source there either (on a firmware build from mid-September), although all eight are present in the flight modes.

edit: btw, I just disabled the companion simulator plugin building, as I don't think we really want this until it's ready 🤭

[3djc]

Opened an issue to make sure I don't forget