Compiles libwebrtc.aar from Google's WebRTC source for Android with
H.264 and AV1 codec support. Includes GitLab CI/CD pipeline that
builds, publishes to Maven Package Registry, and creates releases.

- Dockerfile and build.sh for local builds
- GitLab CI running natively on Ubuntu 22.04 runner
- Maven Package Registry publishing for Gradle dependency integration
- Configurable WEBRTC_BRANCH variable for version pinning
- README with setup instructions, version selection guide, and auth config