private: Add event payload structures to android_logger.h

- common android_event_header_t
- android_event_int_t ANDROID_TYPE_INT payload
- android_log_event_int_t single ANDROID_TYPE_INT event
- android_event_long_t ANDROID_TYPE_LONG payload
- android_log_event_long_t single ANDROID_TYPE_LONG event
- android_event_string_t ANDROID_TYPE_STRING payload
- android_log_event_string_t single ANDROID_TYPE_STRING event

Change-Id: I9e5fccba38e3f230c2c4ec7dec51ed110c460f95