Include installed packages in the "Install Package" quick panel

[FichteFoll]

There have been numerous reports of people trying to install a package and not being able to find it from within PC inside ST because they already had it installed but ignored.

It would be useful if PC listed these package in the "Install Packages" quick panel regardless but annotate them with a "[installed]" tag or similar to signal that this package will not be installed again.

Additionally, PC could add a tag for "[disabled]" packages for even more clarity.