Minor fixes and improvements for crate health code.

Don't rebuild cargo_embargo unnecessarily.

Expand the list of customizations to include TEST_MAPPING and
MODULE_LICENSE_* files

Actually apply the patches.

Don't apply rules.mk.diff.

Format everything with the Android formatting rules, and add a symlink
to the correct rustfmt.toml.

Test: treehugger
Bug: 339424309
Change-Id: I9dbcea1f85d24ae33ada3a69db765e1d0beb8633
7 files changed