[NEW] Allow conflict connection to be made in network pages

[sverhoeven]

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

Since PR #141 it is possible to create new conflicts on the "conflicts table" page.

On the network pages a conflict is drawn without handles.

It would be nice if a conflict edge could be drawn on on the network pages.

Describe the solution you'd like

To not make the UI more busy, it would be nice if I

1. could switch on the conflict editing mode
2. the driven connection handles should disappear and the handles for conflicts should appear
3. A conflict edge could be made by dragging from a formal statement conflict handle to a informal statement conflict handle.
4. switch off conflict editing mode, would hide conflict handles and make driven connection handles appear again.

Describe alternatives you've considered

Just keep using the "conflicts table" page, but that feels less workable as I can not see all statements at a glance.