Migrate 25 crates to monorepo. am: b242094abf am: eaf1a144a4

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/maybe-async/+/3246595

Change-Id: If2909b1f2176f4e857fbb5bd50428c328dc24383
Signed-off-by: Automerger Merge Worker <[email protected]>