Renamed BUILD and WORKSPACE files to BUILD.bazel and WORKSPACE.bazel

[UebelAndre]

The use of BUILD/WORKSPACE vs BUILD.bazel/WORKSPACE.bazel was inconsistent across the repo. This PR updates all files without the .bazel extension to use it (which has the higher priority over the two styles. see here).

Additionally, this PR contains buildifier fixes

[hlopko]

Funny story, we relied on the existing naming of these files - files without .bazel extension were used by blaze (our internal build of bazel) and files with .bazel were ignored.

But I understand the consistency argument, and it's on us to fix our undocumented assumptions internally. I would have chosen files without extension (support for .bazel suffix was added for repos that need to build with bazel and buck at the same time, which is not the case for rules_rust). But we use raze and there I could be convinced to generate files with the suffix, and then to be consistent we need suffices. So shrug :)

[UebelAndre]

I was not aware of any use cases with Blaze nor did I think these rules could be used with Buck. Is any of that documented somewhere? I definitely wasn't trying to break anyone with this change.

[fweikert]

@UebelAndre how did you invoke Buildifier? I'm trying to understand why the formatting problems weren't caught on CI.

[UebelAndre]

@fweikert From the root of the repo, I ran

buildifier -lint=fix -mode=fix -warnings=all -r ./

and I'm using

buildifier version: 3.5.0
buildifier scm revision: 10384511ce98d864faf064a8ed54cdf31b98ac04

[fweikert]

Ok, thank you! bazelbuild/continuous-integration#1129 should fix Buildifier problems on CI.