DNS utils improvements

[The-Loeki]

What does this PR do?

Fix various issues with the dns utils, expand it's functionality and increase it's testing coverage

New Behavior

• Add TLSA, CAA and SSHFP 'intelligent' records
• Various bugs and corner cases fixed
• remove duplicate code and functions
• add solid TLD determination when available

Previous PR's

#39639
#40269

Tests written?

Yes

[garethgreenaway]

@The-Loeki Looks like some of the DNS tests are failing.

[The-Loeki]

@garethgreenaway / @terminalmage
I'd like to ask you guys to merge this if that's OK; I've got the equivalent replacement module WIP as well pending that.

I'd like your opinion before continuing as well:
I've noticed for 2018.3 the refresh_dns() and dns_check() functions got moved to salt.utils.network
That IMHO isn't that logical considering salt.utils.dns.etcetera()

So:

• could you care less?

• or make salt.utils.network.dns and refactor the lot into that

• or refactor dns_check() & refresh_dns() to salt.utils.dns.check()|refresh_resolv(()

• and/or make salt.utils(.network).dns a directory to move more stuff into in expectation of future development

[terminalmage]

I'm not familiar enough with this DNS utils module to comment on it at the moment.

[garethgreenaway]

@The-Loeki Probably makes more sense and more consistent to move all dns related utils into salt.utils.dns

[skorpy2009]

shouldn't this be sshfp record(s)