Merge "Add documentation to README" into main am: beeeef7b34

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2722494

Change-Id: I719ca310a39789edaab5df56c729c3b7ac175fbe
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>