Merge branch 'stable-2.15'
* stable-2.15:
bazlets: Replace native.git_repository with skylark rule
Upgrade bazlets to latest stable-2.15 to build with 2.15.5 API
Upgrade bazlets to latest stable-2.14 to build with 2.14.15 API
Update bazlets to latest stable-2.15 to build with 2.15.4 API
HeartbeatConfigTest: Update file's google-java-format
Format all Bazel build files with buildifier
Update bazlets to latest stable-2.14 to build with 2.14.14 API
Migrate `tools/bazel.rc` to `.bazelrc`
Update bazlets to latest stable-2.14 to build with 2.14.13 API
Update bazlets to latest stable-2.14 to use 2.14.12 API
Change-Id: I9c23fc8f00a6acf50a3784ab2b0e96efd8afcde7
