NIPM: Add flexibility to selecting version of packages

[CL_eisenwr]

As I have come to using NI Package Manager (NIPM) more, I have come across a few user experience issues that need to be improved for NIPM. This is mostly centered around downgrading package version. Most of these are currently available in VI Package Manager

1. For installed packages, you cannot downgrade/change versions of the package. To do this, you must first uninstall the package so you can select the version you want from the Packages screen. (Installed packages are removed from the Packages screen's listing.) There should be at least an option to show the installed packages on the Packages screen so a new version can be selected. It would not hurt to have the ability to select version(s) on the Installed and Updates as well.
2. On the Updates screen, we should be able to select the available versions if there multiple upgrades available.
3. If you install a package that requires a downgrade in a dependency, currently NIPM does not let you install that package. It can be down via the NIPKG command line interface (CLI). There should be at least an option/prompt to allow the downgrade. This capability seems to be able to be added by NI as I was prompted to Allow Downgrade/Removal when I updated InstrumentStudio last year. Our packages should be able to do this prompting as well. At least there could be an option added to NIPM that would allow downgrades/uninstalls so that this could be done via the GUI. Also the dialog could give more information about what specifically the issue is.

Too generic message without any recourse

[Taggart]

Just encountered this. Figured hey it would be easy to downgrade a package. No. It's not obvious at all how to do it. Why? VIPM makes this so easy. Why is it so difficult in NIPM?