Revert RL9 crypto policy to DEFAULT

[priteau]

This should resolve SSH issues with some modern key types such as ed25519.

[gemini-code-assist]

Code Review

This pull request correctly reverts the RHEL 9 crypto policy from FIPS to DEFAULT to allow the use of modern SSH key types like ed25519. The change is well-documented with a new comment and a release note.

However, for this change to be fully effective, a related modification is required in a file not included in this PR's changes. The file etc/kayobe/ansible/maintenance/cis.yml contains an Ansible assertion that explicitly blocks the use of ed25519 keys on Red Hat systems. This assertion was relevant for the FIPS policy but now contradicts the goal of this PR. It should be removed to prevent failures for users who wish to use ed25519 keys.

I've also added one suggestion to improve the clarity of comments in the configuration file.

[Alex-Welsh]

@priteau can we close in favor of #2085?

[priteau]

@priteau can we close in favor of #2085?

#2085 only applies to CI. There was also a recent discussion about relaxing the RL9 crypto policy so that we could use all types of SSH keys.