Support the dav1d decoder in a new codec2 component

This is an experimental project under development and testing. The build
is disabled by default. Most of the source code is copied from
C2SoftGav1Dec but decompression is configured to use dav1d instead of
gav1.

Bug: 277797541
Test: atest -v  CtsMediaPerformanceClassTestCases:android.mediapc.cts.VideoCodecRequirementsTest
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:8f3af1d872428d0d48aab85ab18795fa35d65043)
Merged-In: Iecd54940a47252f635cff29962261193b4c44a2e
Change-Id: Iecd54940a47252f635cff29962261193b4c44a2e