Add SL5 Repos to profile/README.md

[ClemensLinnhoff]

Reference to a related issue in the repository Add a reference to a related issue in the repository.

Add a description Add SL5 Repos to profile/README.md

Take this checklist as orientation for yourself, if this PR is ready for Maintainer Review

• [x] My suggestion follows the governance rules.
• [x] All commits of this PR are signed.
• [x] My changes generate no errors when passing CI tests.
• [x] I updated all documentation (readmes incl. figures) according to my changes.
• [x] I have successfully implemented and tested my fix/feature locally.
• [x] Appropriate reviewer(s) are assigned.