[Documentation]Internews feedback: Add clarity on required expertise for installation

[JoGSal]

Description

Feedback received through Internews highlighted the need to "Make it clear at the beginning of the documentation that intermediate Linux experience is required". This commit adds context on the Quickstart guide, the Installation guide, and the Getting started documentation.

Checks

Docs building

• [ ] Compiles without warnings.

Code formatting and web optimization

• [ ] Uses three spaces indentation.
• [ ] Adds or updates meta descriptions accordingly.
• [ ] Updates the redirects.js script if necessary (check this guide).

Writing style

• [x] Uses present tense, active voice, and semi-formal registry.
• [x] Uses short, simple sentences.
• [ ] Uses bold for user interface elements, italics for key terms or emphasis, and code font for Bash commands, file names, REST paths, and code.