feat(cpn): simulator allow manually setting transmitter battery voltage

[elecpower]

Fixes #5053

Summary of changes:

• add Battery Voltage option to Tools menu

Notes:

• the radio will not update to the new voltage instantly but over a number of adc read cycles as filtered adc averaging is used.
• there maybe instances of rounding variance as the radio uses integers
• the tx battery settings for min max and warn values are only read on sim load ie changes via radio ui will not be detected

[pfeerick]

Thanks for this... looks great!

[VancouverUmbrella]

Thanks, you guys!