[Feature] Standardize what Scoop should do with leftovers outside `%scoop%` on `uninstall --purge`

[o-l-a-v]

Feature Request

Is your feature request related to a problem? Please describe.

A discussion came up in following PR: ScoopInstaller/Extras#16542.

Ideally an app should allow setting a different data directory, so that Scoop can tell it to store it inside %scoop%, but this is wishful thinking.

I prefer and value if a package manager also removes leftovers outside %scoop% on uninstall --purge. But I also see the point about that Scoop shouldn't touch anything outside what it manages.

This should be thought about, discussed, standardized and documented, so that all manifests handles this in the same way. Some suggestions:

• Let --purge also remove data outside %scoop%; there are manifests that do this now.
• Let --purge output directories outside %scoop% if they exist to the terminal.
• Prompt the user to remove directories outside %scoop%.
• Add one more option to uninstall, like --nuke, --remove-all-data or something similar.

Describe the solution you'd like

• Let --purge also remove data outside %scoop%; there are manifests that do this now.

Describe alternatives you've considered

See above.