* Sets macros to allow compiling when Central role is enabled and Observer disabled, or Peripheral enabled and Broadcaster disabled.
* Adds a macro definition for CONFIG_NIMBLE_CPP_IDF to enable different include paths/functionality for IDF / Arduino.
This allows NimBLE options in menuconfig to reduce code size based on
the roles selected (scan/advertising/central/peripheral).
Significant code space can be saved by removing unnecessary roles for the application.
