bazel, bazel_7: move to pkgs/by-name/ba/

[boltzmannrain]

Mostly a pure move keeping pkgs/top-level darwin overrides.
Shared files from pkgs/development/tools/build-managers/bazel/ are copied to each bazel_{version] that uses them instead of figuring out the way to keep sharing. Patch sharing is of limited value, tests sharing looks more reasonable but bazel_7 (or upcoming bazel_8) doesn't use those tests and a new test setup would need to be implemented anyway.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 25.05 Release Notes (or backporting 24.11 and 25.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

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[wolfgangwalther]

big merge conflicts, probably needs to be re-done.

[boltzmannrain]

Rebased, conflicts were not very bazel-specific

[phanirithvij]

bazel_5 and 6 are no more and othe merge conflicts.

[boltzmannrain]

Rebased now 👍

[phanirithvij]

I don't think we should remove the tests

[boltzmannrain]

Removed files were only used by bazel 5&6 but not by bazel 7.
Can return them back as still unused code if that's preferred

[phanirithvij]

I think removal is fine, same reasoning as per #362199, but I wonder why the tests are being neglected.

edit: more merge conflicts

[boltzmannrain]

I think for bazel_7 there was enough to do to just make it build compared to 5&6, and making tests work was substantial amount of work that wasn't yet done, also possibly it could have different set of tests than 5&6 had.

[boltzmannrain]

rebased to fix conflicts

[philiptaron]

You can add yourself too @boltzmannrain as I see you support Bazel a lot in Nixpkgs. CC also @layus

[philiptaron]

This can also be moved in this PR if you also change the package.nix code to bring these into it. bazel_self in particular is finalAttrs.finalPackage. But I will merge this without it.