Hair trimming in pdnsutil #1

[miodvallat]

Short description

This PR is one first step in the path to make pdnsutil code readable and maintainable.
Key changes are:

• every toplevel pdnsutil command is now handled by its own routine, rather than inline in main.
• command declaration is now a map data structure, which allows the nested if ... else if ... else if ... spaghetti in main to be replaced by a find and function pointer call.

Did you know that pdnsutil had two different logic blocks handling the hash-password command, 600 lines of code apart, with the second one being completely dead code as it would have no chance to run?

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 12788952103

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 81 unchanged lines in 8 files lost coverage.
• Overall coverage decreased (-0.01%) to 64.888%

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Files with Coverage Reduction	New Missed Lines	%
pdns/recursordist/recursor_cache.cc	1	84.35%
pdns/recursordist/aggressive_nsec.cc	2	66.17%
modules/lmdbbackend/lmdbbackend.cc	3	73.58%
pdns/recursordist/rec-main.cc	3	62.38%
pdns/recursordist/taskqueue.cc	11	34.15%
pdns/recursordist/test-syncres_cc1.cc	13	89.37%
pdns/recursordist/syncres.cc	14	79.97%
pdns/recursordist/rec-taskqueue.cc	34	40.14%

Totals
Change from base Build 12766545506:	-0.01%
Covered Lines:	126327
Relevant Lines:	163842

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💛 - Coveralls

[chbruyand]

Very nice to have split the main(). On other binaries we have been tending to explicit short variable names instead of adding a bunch of NOLINT(readability-identifier-length) (which decreases readability IMO). Otherwise LGTM !