Add libaidlmetadata_headers

This is needed for device libraries to use the definition of
AidlInterfaceMetadata without linking to
AidlInterfaceMetadata::all and all the real data it exposes,
which is known to be big.

Bug: 110261831
Test: pass
Change-Id: If30132c82a41d986b685bd9e02b92da889b83d24
1 file changed