Add default implementation of AIDL EVS interface

This implementation is used for the emulators.

Bug: 218588089
Bug: 270753093
Test: 1. Build cf_x86_64_auto lunch target
      2. Launch cvd in the accelerated graphics mode
      3. Run evs_app and confirm the color bar pattern is shown on the
         display.
         > adb root && adb shell evs_app --test
Change-Id: I8179e74fc9f0b9547316368fca507e5c62ca5680