Install and upgrade with parameters

[itowlson]

The Install and Upgrade commands need to provide a way for users to enter parameters. The user experience needs to be pretty smooth here because users don't want to wade through confirming default values for 70 different parameters, or to have to type 14 overrides perfectly with no way to undo except to back out the entire operation, or to enter the same values repeatedly every time they redeploy. Not to mention that we need to work within the very limited VS Code UI!