Add more controls to the menu bar

[Peregrine05]

Chunky should make more use of the menu bar.

Controls that exist in the context menus of the Map tab and Render preview tab should also exist in the menu bar under a Map dropdown menu and a Render preview dropdown menu, respectively. This is to provide an alternative location for the controls, so that new users who do not know that the map and render preview can be right-clicked can still find and access the controls. Additionally, at large canvas resolutions, the render preview becomes invisible, rendering controls located in its context menu inaccessible.

[NotStirred]

The undo and redo affecting every action should be its own issue, as that's an enormous amount of work