IP: Change DNS nameserver code to use libswoc.

[SolidWallOfCode]

Part of a coverity effort to remove ats_ip_copy. Primarily this involves moving from sockaddr to IPEndpoint. Some of the code uses the obsolete IpEndpoint (a precursor to swoc::IPEndpoint).

This depends on libswoc 1.5.9, which has many improvements in the IP support code driven by this effort.

[bryancall]

@bryancall is going to take over this PR

[ywkaras]

[approve ci]

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. Marking it stale to flag it for further consideration by the community.

[brbzull0]

@bryancall I can take care of this if you want.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. Marking it stale to flag it for further consideration by the community.