Switch car-lib over from doclava to metalava

The platform API files are about to switch to signature
file format v2, which doclava cannot parse, so updating
this build to using API check via metalava instead of
doclava.

Note: Metalava checks for additional API and docs problems which
doclava did not; some of these are errors which would fail the
build. Therefore, we turn off these warnings until the source
code is	fixed.

Test: make docs
Bug: 122724077
Exempt-From-Owner-Approval: Large-scale tooling change
Change-Id: Ib7cab01e85e7032ffbc7cf03771a59b8f2bfd46d
1 file changed