fix: don't erase previous record from /etc/hosts

[imanenami]

Changes:

• Preserve other /etc/hosts records on update

[marcoppenheimer]

Great! Blazingly fast too.
Could we add a unit-test for this and fix the failing ones? I'll approve early though 👍🏾
Oh, and open a mirror PR on K8s, but that's lower priority.

[phvalguima]

I think we are still missing some corner cases such as IP changes. Even converting to a set(), this case would be considered different and, depending on the order, the older ones may end up being prioritized.

I have a quick proposal: we could first check if either fqdn or hostname is present in the host_entries, if yes, then we remove that line.

[phvalguima]

Thanks @imanenami, I left one last remark but I think other than that, we are good to go.