cargo_embargo: new cargo2android tool

A fork of cargo2android, initially aimed at big imports like crosvm.

* Faster run time when there are many packages (30 min -> 1 min for
  crosvm).

* `--reuse-cargo-out` feature allows iterating on most of the config
  with sub second run time.

* Most options can be specified per-package.

Bug: 261486161
Test: ran on crosvm and checked diffs
Change-Id: Iaf3f4732e828a6f8b281f0e63fe1e0e1e9e98631
5 files changed