Nix script

[AVtheking]

What kind of change does this PR introduce?

Created a installation script to install the packages of the project

Issue Number:

Fixes #2385

Did you add tests for your changes?

No

If relevant, did you update the documentation?

Summary Created a nix flake to install the packages required to run and setup the talawa project.

Does this PR introduce a breaking change? No

Have you read the contributing guide?

Summary by CodeRabbit

• New Features

  • Introduced Nix flake configuration to manage dependencies for Git, Node.js, TypeScript, FNM, and Redis.
  • Configured Redis to store data in a specified directory for better data management.

• Chores

  • Added a setup script to automate the installation of the Nix package manager and environment setup for development.