Install locally on a machine with no-root, docker, apt, yum, and apk via nix package manager.

[bluestero]

Description

So, I worked on a template to contribute to Codesphere which involved installing Stirling-PDF and its dependencies locally. The catch was that there was no root access and packages should be installed via Nix package manager (nix-env). So it took me many many hours to research and find a way to make it work using no-root and Nix. So this PR contains my edit in the LocalRunGuide.md file where I added instructions for the no-root and Nix method.

Also, I caught a small line break issue and fixed it along the way:

Closes #1175

Checklist:

✅ I have read the Contribution Guidelines. ✅ I have performed a self-review of my own code. ✅ I have commented my code, particularly in hard-to-understand areas. ✅ My changes generate no new warnings.

Contributor License Agreement

By submitting this pull request, I acknowledge and agree that my contributions will be included in Stirling-PDF and that they can be relicensed in the future under the MPL 2.0 (Mozilla Public License Version 2.0) license.

(This does not change the general open-source nature of Stirling-PDF, simply moving from one license to another license)