Improvements to plugin

[nagkumar]

Directories should be selectable (browse & select), rather than they have to be typed now.

Package names can also browse and selectable

similar to what exists in application config

Other parameters should also be selectable (display all allowed parameters in a table and all the valid options if exits should allow user to select)

in similar lines to

Make it so UI friendly that, none has to search for what are the valid options for pitest framework allowed options