docs: Combines information in README.md

[gruyaume]

Description

With the badges now in the README.md, we have redundante information regarding links to SD-Core bundles in Charmhub. This PR removes the unnecessary links and only keeps the badges which are clickable.

Checklist:

• [ ] My code follows the style guidelines of this project
• [ ] I have performed a self-review of my own code
• [ ] I have made corresponding changes to the documentation
• [ ] I have added tests that validate the behaviour of the software
• [ ] I validated that new and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules
• [ ] I have bumped the version of the library