chore: use hugepages lib v0.6

[gruyaume]

Description

Here we use the hugepages lib v0.6 which reduces complexity in the upf k8s charm. There is no more need for the charm to emit custom events that are listened to by the lib (which was unnecessarily complicated).

This PR has to be merged first:

• https://github.com/canonical/kubernetes-charm-libraries/pull/59

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