treewide: Update deprecated CONFIG_LIB_CPLUSPLUS usages

This commit updates all deprecated `CONFIG_LIB_CPLUSPLUS` usages to:

* check if the Zephyr minimal C++ library is enabled using
  `CONFIG_MINIMAL_LIBCPP` instead of relying on the
  `CONFIG_LIB_CPLUSPLUS`-based inference.

* select `CONFIG_REQUIRES_FULL_LIBCPP` when there exists a component-
  level C++ standard library dependency. This allows a component to
  declare C++ standard library dependency without designating a
  specific libray implementation.

* select the correct type of C++ standard library implementation to use
  through one of the `CONFIG_LIBCPP_IMPLEMENTATION` choices.

Signed-off-by: Stephanos Ioannidis <stephanos.ioannidis@nordicsemi.no>