Add a possibility to specify the verbosity flag for the install-scripts execution

[YuliiaKovalova]

It would be very handy to be able to have a full verbosity logs reported for scripts execution.
Recently we have had a bug that we weren't able to investigate due to lack of information:
dotnet/install-scripts#466

[aparnajyothi-y]

Hello @YuliiaKovalova, Thank you for creating this issue and we will get back to you once we have some feedback :)