Improvements for GTK4 UI

[koeppea]

As announced here are a couple of further observations in the GTK4 UI:

1. No Ettercap Icon: In the task-bar as well as in the task switcher (Alt+Tab), the default icon is shown instead of the ettercap icon

2. In Connections, Profiles and SSL Intercept list-view, right-clicking any entry, the context menu is popping up in the lower-left corner of the list instead next to the pointer.

3. When toggling a toggle-entry in the menu, the menu closes. In GTK3 behavior, the menu remained open for further selections.

4. Profile details and Connection details dialog is too small to display the content and cannot be resized - scrollbars appear

5. Does GTK4 not provide a dialog specialized for keystroke shortcuts? The current dialog is also quite small.

6. About dialog dialog also doesn't show the icon.

7. Width of the new redirect dialog is too narrow. Anything other than 0.0.0.0/0 requires scrolling within the field which is especially problematic with IPv6 addresses.

That's it so far. Anyway, especially for the bright theme in my opinion the GTK4 design looks pretty lifeless, but that's nothing we can influence.