Create GetPrebuiltFileInfo to Mixed builds cquery api

prebuilt_file Bazel targets do not have any build actions per se, but
return a PrebuiltFileInfo provider that determines installation rules.
To integrate this info into mixed builds, add a `GetPrebuiltFileInfo` method to
the API.

Bug: 280094612
Test: unit tests for prebuilt_etc in the next CL of this stack
Change-Id: I79da6b75b6a6cbd30869860d3620aeda731ea36a