Import 'mls-rs-codec' crate

Request Document: go/android-rust-importing-crates
For CL Reviewers: go/android3p#cl-review
For Build Team: go/ab-third-party-imports
Bug: http://b/328421610
Test: m libmls_rs_codec

Change-Id: I4d927a57e949b3f40d8024d10ad84149e26f2e2e
25 files changed