Merge "Add documentation to README" into main am: beeeef7b34 am: 12a3909628 am: 307bc8bc52

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

Change-Id: I546079a258592c8e6c2cec05707b3b6391557f97
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>