graphics/common: add stable AIDL types

Gralloc 4 (IAllocator 4.0 and IMapper 4.0) is a HIDL interface that
will support getting and setting buffer metadata. To allow vendors to
easily add arbitrary metadata, the interface accepts metadata as a
bytestream.

Some of the metadata gralloc 4 will use is already defined in HIDL.
Unfortunately, some of the metadata was defined in composer which
is a binderized HIDL interface. IMapper is a HIDL-SP interface
so it cannot reuse composer's definitions.

Since the display HIDL interfaces will likely move to stable AIDL
soon, redefine the metadata in stable AIDL. IMapper uses a byte
stream so the types can be defined anywhere. By redefining the types
in stable AIDL, we won't have three definitons of the exact same
type in the future.

Bug: 141632767
Test: N/A - This patch just adds types. There are tests in the patches
      that use the types.

Change-Id: Icaf6200c327d71a41d66a3e66dd6890ab5c2041a