pkgs/by-name: add version pins

[quantenzitrone]

Proof of concept implementation of NixOS/rfcs#192

Things done

• Built on platform:
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• Tested, as applicable:
  • NixOS tests in nixos/tests.
  • Package tests at passthru.tests.
  • Tests in lib/tests or pkgs/test for functions and "core" functionality.
• Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • Package update: when the change is major or breaking.
• NixOS Release Notes
  • Module addition: when adding a new NixOS module.
  • Module update: when the change is significant.
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.

---

Add a 👍 reaction to pull requests you find important.

[qweered]

Conceptually looks good, what are next steps for this pr?

[quantenzitrone]

probably get the rfc merged first, or do you think this is small enough to be done without the rfc?

[qweered]

we do need to hear opinion of @NixOS/nixpkgs-core at least

[wolfgangwalther]

we do need to hear opinion of @NixOS/nixpkgs-core at least

I'm not sure what the question to the core team here is. The core team generally is not a code owner that should be pinged for review. However, if local consensus can't be reached, we can surely help out.

In this case, the PR is a draft to support an ongoing RFC. The RFC is not done, yet. The PR fails CI. Nothing to do here.