Require proto rules to be loaded by buildifier (#1310)

* Require proto rules to be loaded by buildifier

Because the rules are moved into the repository the loads become mandatory with Bazel@HEAD.

Add new warning for each rule and symbol that needs to be loaded. Buildifier doesn't handle well loading from different bzl files in a single warning.

Enable all proto rules warning by default.

* Format with gofmt

* Add missing quote

* Add and regenerated docs

* Fix tests

* Remove \n\n