extension changing current selection

[Neon22]

Feature request Summary:
Inkscape signals to an extension the ids of the currently selected items in the UI.
However the extension cannot set/change a selection on returning.
I propose that this is handled in the same way inkscape currently does.

Reasons for doing this:
E.g. A user selects one line and the extension selects all lines that are asssociated in some way (e.g. same length, same metadata, color, or anything the extension is trying to help with).
This might be a side effect of doing some work and helps the user to do further work by this collection method.
E.g. an extension in the bobbin lace tools that if a user selects an edge, will return all adjacent edges of same thread class, so user can nudge the pattern and see the effect in all the clones.

Specifically:
Inkscape signals which items are selected by using the id of the items in an option.
- options.ids

The extension can query this and know what the user has selected.
The extension can call a subprocess of inkscape and also set these values to do queries. E.g. the perspective extension shows this.

However when the original inkscape receives info back from the extension, it does not look at this and set the users selection to a possibly new one.

Detail:
inkex.py shows how the self.options.ids are traversed to gather the items
Possibly an inkex.setselected() to match the inkex.getselected(). If this is not called then no options.ids will be sent back.

The internal inkscape dispatching code would need to look for the option.ids coming back to it. Then change the selection.