Replace command line parsing library with a new one

[alexandre-lecoq]

We need a command line parser that matches our need, is stable, and maintained.
There are lots of parsing packages available out there, but most a small abandoned projects.

I selected 4 candidates for this purpose :

Github	Nuget	Comment	Usage & Popularity	Days / Release
commandline	CommandLineParser 2.6.0	Used from begining to 2018-05-28 fa9198d	1	62
CommandLineUtils	McMaster.Extensions.CommandLineUtils 2.4.4		2	12
PowerArgs	PowerArgs 3.6.0		3	191
CommandLineParser	CommandLineArgumentsParser 3.0.20	Used from 2018-05-28 to now fa9198d	4	162

McMaster.Extensions.CommandLineUtils looks like a good candidate, but the change has to be studied carefully.
Nowadays QueryMultiDb is used automatically by other tools which generates its command line.
Therefore, changing the commandline syntax in the tool would be a breaking change.
The migration to a new parsing library must retain backward compatibility.