More helpful pdnsutil help output

[miodvallat]

Short description

This is another take at #12350 ("Group pdnsutil usage by topic"). The dictionary of pdnsutil commands is extended with a "command group" and the short help text, for every command. This allows these help texts to be output in groups, with alphabetical ordering within each group, automagically.

Doing this also exposes a few commands which lack help texts, these can either remain hidden or get gifted a nice help text (to be discussed in this PR).

The grouping of commands is stolen borrowed from #12350 and open for discussion as well. The changes in this PR allow for group assignment to be changed very easily, as well as new groups created, if deemed useful.

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)

[coveralls]

Pull Request Test Coverage Report for Build 12931605740

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 33 unchanged lines in 11 files lost coverage.
• Overall coverage decreased (-0.004%) to 64.697%

---

Files with Coverage Reduction	New Missed Lines	%
modules/gpgsqlbackend/gpgsqlbackend.cc	1	88.62%
pdns/signingpipe.cc	1	85.25%
pdns/dnsdistdist/dnsdist-crypto.cc	1	76.01%
ext/json11/json11.cpp	1	64.49%
pdns/misc.cc	2	62.71%
pdns/remote_logger.cc	3	54.26%
modules/gpgsqlbackend/spgsql.cc	3	68.18%
pdns/recursordist/test-syncres_cc1.cc	5	89.87%
pdns/packethandler.cc	5	72.48%
pdns/recursordist/syncres.cc	5	79.86%

Totals
Change from base Build 12927190209:	-0.004%
Covered Lines:	127817
Relevant Lines:	166470

---

💛 - Coveralls