This resolves#5523
While bumping `com.android.tools.build:gradle:3.1.2` to `3.3.0`, some other plugins/artifacts/maven repo/buildscripts have to be updated:
- gradle (wrapper) need to upgrade to 4.10.x
- protobuf gradle plugin need to bump a version compatible with gradle version.
- need add `google()` and `jcenter()` repos for android (otherwise `com.android.tools.build:aapt2:3.3.0x` and `trove4j` will not be found resp.)
- need to accept license for Android "build-tools;28.0.3" in kokoro env.
For Bazel, we upgrade to protobuf 3.6.1.2 and javalite HEAD to fix
incompatibilities in newer Bazel releases.
compiler/Dockerfile is unused, so it was removed instead of being updated.
protoc no longer includes codegen for nano, so we remain on the older protoc
any time nano is used.
Protobuf now requires C++11 when compiling, so windows was swapped to
VC 14.