UX: Unify the installed plugins views

[joaquimrocha]

Describe the bug

After our Contribufest at KubeCon, it was clear that having an installed view for plugins installed by the Plugin Catalog + a list for all installed plugins is not a great idea, as many were looking for their development plugin in the Plugin Catalog installed list.

I think the easiest way to prevent this problem is to show all plugins in the Plugin Catalog installed view. Since we may not be able to uninstall plugins that have no been installed by the Plugin Catalog, we could have them in a different category. Maybe we show two tables, e.g.:

Installed from the Plugin Catalog
[...]

Other Plugins
[...]

We should also link from this page to the respective plugins' details/settings.

To Reproduce

Steps to reproduce the bug:

1. Use Headlamp desktop versionl; Go to the Plugin Catalog view.
2. Click the installed list: only plugins installed by the Plugin Catalog are shown there

Environment (please provide info about your environment):

• Installation type: Headlamp for desktop
• Headlamp Version: 0.26.0

[skoeva]

related: #2545

[vyncent-t]

PR for this is on the plugins repo

headlamp-k8s/plugins#117