[FEATURE REQUEST] Remove old versions of PowerShell modules.

[mnrubino]

Please confirm these before moving forward.

• I have searched for my feature proposal and have not found a work-in-progress/duplicate/resolved/discarded issue.
• This proposal is a completely new feature. If you want to suggest an improvement or an enhancement, please use this template.

Describe the new feature

I would love it if UniGetUI would remove all of those old versions PS modules on my systems. Maybe have a settings option to not do that for those who don't want it.

Describe how this new feature could help users

It's currently a PITA to keep installed modules clean.