Rename module dist files

This makes the filenames of the disted artifacts (api txts and stubs)
match the module name of the modules they're from. This matches the
naming scheme used by java_sdk_library, which should make the future
transition to this build rule easier.

Bug: 149293194
Test: lunch sdk_phone_armv7 && m sdk dist && find out/dist/apistubs
Change-Id: I076f30931bf2524d57703873cd7de25b3f23b457