auth: added a new config for direct queries of dnskey signature

[d-wibowo]

Short description

Addresses the feature request that I made on Issue #14372.

Added a new setting called direct-dnskey-signature, which allows for the direct retrieval of DNSKEY signature from the backend.

Checklist

I have:

• read the CONTRIBUTING.md document
• compiled this code
• tested this code
• included documentation (including possible behaviour changes)
• documented the code
• added or modified regression test(s)
• added or modified unit test(s)
• checked that this code was merged to master

[coveralls]

Pull Request Test Coverage Report for Build 10521093224

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 2 of 2 (100.0%) changed or added relevant lines in 2 files are covered.
• 6362 unchanged lines in 125 files lost coverage.
• Overall coverage increased (+5.7%) to 64.677%

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Files with Coverage Reduction	New Missed Lines	%
pdns/dnspacket.hh	1	94.44%
pdns/auth-catalogzone.hh	1	66.67%
pdns/uuid-utils.cc	1	42.86%
pdns/protozero.cc	1	40.0%
pdns/libssl.hh	1	0.0%
pdns/recursordist/nod.hh	1	92.59%
modules/remotebackend/zmqconnector.cc	2	68.55%
pdns/epollmplexer.cc	2	83.75%
pdns/recursordist/rec-tcp.cc	2	65.5%
pdns/snmp-agent.hh	2	75.0%

Totals
Change from base Build 10516284382:	5.7%
Covered Lines:	124618
Relevant Lines:	162022

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💛 - Coveralls