Range test is excluded on every target as of 2.8, so set
MESHTASTIC_EXCLUDE_RANGETEST=1 globally in [env] build_flags and drop the
now-redundant per-variant flags from esp32, rak11200 and stm32.
Guard RangeTestModule.cpp with the same condition used in Modules.cpp so the
translation unit compiles to nothing rather than relying on --gc-sections to
strip it, and always report RANGETEST_CONFIG in the device metadata
excluded_modules bitmask so clients hide the config.
Ben Meadors
cad3a3a5c7