Initial implementation of the bazel sandwich

The "bazel sandwich" is a mechanism for bazel to depend on make/soong
outputs. The name comes from the fact that bazel is now at the top
and bottom of the build graph. This is intended to allow us to work
on converting the partition builds to bazel while not all of the
dependencies of the partition have been converted.

It works by adding the bazel_sandwich_import_file rule, which emits a
dangling symlink that starts with bazel_sandwich:, and includes
information that the aquery handler in soong reads. The aquery handler
rewrites the symlink so that it points to a file generated by
make/soong, and adds a ninja dependency from the symlink to the file
it's targeting.

This allows us to depend on make-built files from bazel, but notably
it doesn't allow us to depend on analysis-time information from make.
This shouldn't be a problem for the partitions, but limits the use of
the bazel sandwich to similar, less complicated types of builds.

go/roboleaf-bazel-sandwich

Bug: 265127181
Test: m bazel_sandwich
Change-Id: Ic41bae7be0b55f251d04a6a95f846c50ce897adc