Merge history of opt/net/ethernet

Renamed files/directories:
java/ --> service-t/src/
tests/ --> tests/ethernet/
Android.bp --> (removed)
OWNERS --> (removed)
.gitignore --> (removed)

BUG: 222234190
TEST: TH
Ignore-AOSP-First: Move with history done per-branch
Merged-In: I1530fcd6d47b7538ae31725432728e725910e3a2
Change-Id: I6bf4ae243c152001cc80d99d9c665c43353b2b55