Allow plugins to open other plugins

[danyill]

As we have more plugins it would be useful to be able to open one plugin from another.

For example, the Communication Explorer that SprintEins have developed might wish to open a detail view in a subscription editor.

I expect as more extensions are built we will want to "deep link" parts of OpenSCD to other parts and be able to pass parameters to plugins and it would be good to have a mechanism for this.

[pascalwilbrink]

This might be solvable through a NavigationEvent ? OpenSCD-core can subscribe to this event