[automerger skipped] [DO NOT MERGE] Add RBE mk file to support bootstrapping...

[automerger skipped] [DO NOT MERGE] Add RBE mk file to support bootstrapping RBE and setting relevant am: 7298be1b am: edd7e730 -s ours am: 428006cf -s ours am: 7f5263a2 -s ours

am skip reason: subject contains skip directive

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/+/12468471

Change-Id: I835556f2b41ff01bc09b8b5fd64b3902b959336a