Migrate 25 crates to monorepo. am: 8d7f31ba01

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/synstructure/+/3247562

Change-Id: Ib76b199617628cc197e0ec8f596007daf6022fbf
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>