Change Markdown Linting action to rumdl and update config

[jackspiering]

CI/CD: Updated the Markdown Linting action to use a different GitHub action and modified its configuration.

Description

rumdl is faster and updates compared to the current linter. See: https://github.com/rvben/rumdl

Related Issues

• None.

Verification

Tested it on a forked repo: jackspiering#21

Checklist

• I have performed a self-review of my code and followed the templates structure.
• I have added verification that the stack works as expected.
• I have updated necessary documentation (e.g. frontpage README.md ).
• I have selected the correct label(s) for this PR.

Additional Context

• None.