Add add3prf.py and call it from get_rust_pky.py

* add3prf.py can be called in existing rust package directories
  to normalize METADATA, OWNERS, and other LICENSE* files.
* Add option in get_rust_pkg.py to call add3prt.py and add
  required files for 3rd party reviews.

Bug: 170254513
Test: call add3prf.py in external/rust/crates/*
Test: get_rust_pkg.py --add3prf quote remain paste
Change-Id: I70ed5942847716af2ca740a91e7ecde50543b7a0
3 files changed