chore: incorporate small findings from qgate review

[tom-rm-meyer-ISST]

Description

During Review of the QGate #127, a few things were that small that I directly incorporated them.

Why

Compliance to TRG is needed. Beside the issues listed, I added the QGate check workflow so that you automate a few checks a little :)

Issue

Following issues are resolved:

• TRG 1.01: Information about Policy Hub missing in Readme. #140 -> link to docs
• TRG 1.02 / TRG 5.07: Documentation misses dependency update #141 -> added one line for installation
• TRG 5.02: Prerequisites missing in helm README #144 -> added prerequisites

Checklist

Please delete options that are not relevant.

• I have followed the contributing guidelines
• I have performed IP checks for added or updated 3rd party libraries
• I have created and linked IP issues or requested their creation by a committer
• I have performed a self-review of my own code
• I have successfully tested my changes locally
• I have added tests that prove my changes work
• I have checked that new and existing tests pass locally with my changes
• I have commented my code, particularly in hard-to-understand areas
• I have added copyright and license headers, footers (for .md files) or files (for images)

[evegufy]

Thanks for providing the PR, really handy :)
Just one comment.