Squashed commit of the following:

commit 00c2b21c8fa9004aa697c01961c46fe0329cffe8
Author: Kevin Graney <kmg@google.com>
Date:   Tue May 9 14:39:03 2023 -0400

    Add TEST_MAPPING

commit ed8ac8d9261350a5387039f36027584491e04745
Author: Kevin Graney <kmg@google.com>
Date:   Tue May 9 10:48:45 2023 -0400

    Depend on private-join-and-compute abseil

commit 1907d032ccf04e256a3900d0db55d56e861f0ba6
Author: Kevin Graney <kmg@google.com>
Date:   Thu May 4 15:48:54 2023 -0400

    Fix METADATA filename typo

commit b77a752a66406082974f12ee3455742337e02f85
Author: Kevin Graney <kmg@google.com>
Date:   Thu May 4 10:24:04 2023 -0400

    Add build rules

commit 132bec1222d439625cf8ae692c03ce518945cba2
Author: Kevin Graney <kmg@google.com>
Date:   Thu May 4 10:24:26 2023 -0400

    Add abseil

commit 410c261bf1629f65651d2b7bc53a188e5dba2211
Author: Kevin Graney <kmg@google.com>
Date:   Tue Apr 25 13:27:39 2023 -0400

    Add metadata files

commit 827d2aa7
Author: Karn Seth <karn@google.com>
Date:   Wed Apr 19 11:12:58 2023 -0400

    initial commit

Change-Id: I8f92eeb3857f7e65fdf495e76a4967ae69ed5878
(cherry picked from commit e1220b40)