Improvement: Introduce markdown linter

### What

The goal is not to ensure a specific format but to have consistency in the project.
With a linter, we also want to reduce the possibility of errors and maximize compatibility across different Markdown viewers.

### How

Making use of rules_lint that we already use for other linters and supports markdown
https://github.com/aspect-build/rules_lint#supported-tools

### Estimates for realization

_No response_

### Category

- [ ] Affects Detailed Design

### Requirements / Architecture

- [x] Requirements / Architecture are not affected by this change?

No files or tests are named. Start by reviewing the repository’s existing linter configuration and the rules_lint Markdown support linked in the issue. Add the Markdown linting integration where the current linters are configured, then verify that the project’s Markdown files pass consistently.

Written by the indexing model from the issue text.