Added doxygen documentation for FCB API. Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
move fcb.h to fs/fcb.h and create a shim for backward-compatibility. No functional changes to the headers. A warning in the shim can be controlled with CONFIG_COMPAT_INCLUDES. Related to #16539 Signed-off-by: Anas Nashif <anas.nashif@intel.com>