Unite Circular View and Zoom View into a more common Zoom View widget

Currently, Zoom View and Circular View are two widgets that can be shown to a user simultaneously. It doesn't have much sense.

Next should be done:

1. Zoom View should be able to draw both linear and circular sequences with annotations. The type of the drawn sequence should be defined by the sequence object type (is it marked as circular or not).
2. The "Save circular view as image" functionality should be moved to the "Export Image" dialog.
3. Restrictions sites map widget should be placed to the right of the Zoom View widget like it is placed in Circular View now.
4. Zoom View local toolbar should contain zoom buttons for all sequence types.
5. "Show/hide restriction sites map" button should be added to a local toolbar for circular sequences.
6. Changing sequence type should cause changing Zoom View type.
7. "Toggle Circular View" button should be removed from the global toolbar.
8. "Toggle Circular View" button on the single sequence view should change the sequence type. It should have a circular icon for a linear sequence and a linear icon for a circular sequence.
9. All addition features should be moved from the circular_view plugin to the core libraries.
10. circular_view plugin should be removed. Do not forget to update deploy scripts.