Add nix package manager

[adrian-gierakowski]

Tool information

• Tool name: nix
• Add or update? Add
• Desired version: latest (currently 2.3.2)
• Approximate size:
• If this is an add request:
  • Brief description of tool: The Purely Functional Package Manager
  • URL for tool's homepage: https://nixos.org/nix/

Area for Triage:
??

Question, Bug, or Feature?:
Feature

Virtual environments affected

• [ x ] macOS 10.15
• [ x ] Ubuntu 16.04 LTS
• [ x ] Ubuntu 18.04 LTS
• Windows Server 2016 R2
• Windows Server 2019

Can this tool be installed during the build?
Yes, there is an action which does it: https://github.com/cachix/install-nix-action
Install takes around:
15s on Linux
90s on MacOs

Are you willing to submit a PR?
Yes

[thejoebourneidentity]

Thanks for your suggestion 🙏. Considering how popular this tool is, and how easy it is to install during your run, it's not something we will add to the image at this time.