Add Fahrenheit temperature unit config options

[TheBengineer]

Adds Fahrenheit (ºF) config variants for all existing display configurations.

• Created WLConfig_BW_F, WLConfig_EINK_F, WLConfig_BWI_F, WLConfig_RGB_White_F, WLConfig_RGB_Black_F
• Each uses TEMPUNITS_MODE=1 and a distinct output filename (_f suffix)
• The existing Celsius infrastructure (IsCelsius, PrintableTemperature, toFahrenheit) was already in place, just needed config wiring
• Updated server and test runners to include the new variants

Tested on a Raspberry Pi with the weather display.