Issue 2683 - Install Nix in cdk-environment EC2

[patchwork01]

Make sure you have checked all steps below.

Issue

• My PR addresses the following issues and references them in the PR title. For example, "Issue 1234 - My Sleeper
  PR"
  • Resolves Use Nix for builds on cdk-environment EC2 #2683

Tests

• My PR adds the following tests OR does not need testing for this extremely good reason:
  • Tested in AWS

Documentation

• In case of new functionality, my PR adds documentation that describes how to use it, or I have linked to a
  separate issue for that below.
  • Update documentation to use Nix instead of CLI in environment EC2 #2819
• If I have added, removed, or updated any external dependencies used in the project, I have updated the
  NOTICES file to reflect this.