Add Powershell scripts with autocomplete

[ate47]

Hello,

This pull request give Powershell users autocompletion with the RDFHDT's CLI commands.

I tried to be as generic as possible to let non Powershell users add their parameters.

Autocompletion for each command

Autocompletion for RDF2HDT the -rdftype argument

I've fixed few CLI classes and added to the Readme some info.

Tested with both Windows Powershell 5 and Powershell 7