Protoc-java-resource-names-plugin

- Stop generating subclasses for multi-pattern resources from gapic v2
- Safeguard new multi-pattern resources behind `betaApi`

Fix the incorrect equals() override in multi-pattern resources (73)

- Generate all resource classes referenced by child_type
- Generate all message-level resource classes
- Support multi-pattern resource name
- Support file-level resource_definition annotations
- Support common resources
- Other bug fixes

**New Implementation**
- Escape Java keywords (40)

**Dependencies**
- Update protoc to 3.6.1 (41)

**Build**
- Bazel-based codegen (38)