KAA-229: add kaa_platform_protocol.[ch]
KAA-229: move platform protocol functions out of kaa.[ch]
Merge branch 'c_sdk_refactoring' of https://github.com/kaaproject/kaa into c_sdk_refactoring
Merge branch 'c_sdk_refactoring' of https://github.com/kaaproject/kaa into c_sdk_refactoring