Swap out legacycrypt for crypt-r for Python 3.13+

[jeremycline]

Description

PR #3070 pulled in legacycrypt to replace the removed crypt module. legacycrypt hasn't been updated since it was initially pulled out of Python's stdlib in 2019 (Python 3.7). crypt-r pulls in the module as it was in Python 3.12. While there's been no major developments since 3.7, it's more likely to be kept updated for any breakages in future Python releases.

It's also already packaged for Fedora and means one less package for me to maintain so that would be nice.

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[nagworld9]

@jeremycline Thanks for the change. We implemented temporary workaround to use legacycrypt to fix importing crypt issue on agent start. But the code that's need crypt() function from crypt module is owned by(JIT) team. We started a discussion with them and will let JIT team to handle this.

[nmeyerhans]

My suggestion would be to avoid handling hashing here at all, and instead leverage chpasswd for password setting. It has a few advantages over the current implementation:

1. It's a common tool (part of the shadow suite) and well tested
2. It integrates with pam, so system-wide configuration applies for settings like the hash algorithm
3. It avoids taking a dependency on legacycrypt or some other crypt frontend

You can look at the cloud-init sources for an example of how to use chpasswd in this scenario.