Allow setting notify_allowed in Recursor API for forwarded zones

[bakern]

Closes #14116

Short description

Allows setting notify_allowed when adding forwarded zones through the Recursor API. This works with the new YAML settings and the old-style settings. If notify_allowed is not sent or is set to false, the behavior is unchanged. If notify_allowed is set to true the Recursor will allow NOTIFY to clear cache for the given zone.

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)

[omoerbeek]

Hello, thanks for the PR. I'm wondering about the old config case. I do not see the code that handles notify_allowed for that. I'll try to test soon.

[omoerbeek]

I was misdiagnosing earlier, there is code to handle notify, also for old-style configs.
Added one commit to make sure notify_allowed flag is also represented in zones objects returned.
Before merging, this PR should get regression tests.

[coveralls]

Pull Request Test Coverage Report for Build 9265491441

Details

• 4 of 7 (57.14%) changed or added relevant lines in 2 files are covered.
• 63 unchanged lines in 14 files lost coverage.
• Overall coverage decreased (-0.02%) to 64.595%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pdns/recursordist/ws-recursor.cc	3	6	50.0%

Files with Coverage Reduction	New Missed Lines	%
pdns/packethandler.cc	1	72.86%
modules/gpgsqlbackend/gpgsqlbackend.cc	1	88.62%
pdns/backends/gsql/gsqlbackend.hh	1	97.71%
pdns/pollmplexer.cc	1	83.66%
pdns/signingpipe.cc	2	85.48%
pdns/recursordist/test-rec-tcounters_cc.cc	2	95.74%
pdns/dnsdistdist/dnsdist.cc	2	68.19%
ext/json11/json11.cpp	3	62.72%
pdns/dnsdistdist/dnsdist-carbon.cc	3	61.56%
pdns/recursordist/rec-tcp.cc	4	62.3%

Totals
Change from base Build 9255528069:	-0.02%
Covered Lines:	124282
Relevant Lines:	161640

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💛 - Coveralls

[bakern]

Thanks @omoerbeek!

I compiled and tested with your change, that is very helpful. One last thing I was wondering, should we also add the notify_allowed flag to the /zones endpoint when listing all zones, or is that too much detail for that endpoint?

Before merging, this PR should get regression tests.

Please let me know if there is anything I need to do for this.

[omoerbeek]

Added simple test and rebased.