Creating Edit Menu UIs

[MartinMuzatko]

This issue contains the next discussion for planning the next steps of the editing menu

The main document to work with is here: https://github.com/inexorgame/inexor-core/wiki/Edit-Menu-UIs

To contribute, please discuss your concerns or questions here in this issue. Otherwise you can add your ideas to the wiki directly.

Current tasks:

• Define what pages/menus we need
  • Define contents, actions for each page
• Define how to get to these menus (Keybindings? Menu point in main menu while editing?)

Roadmap:

• Define roughly which contents we need to display and in which menus this can fit into
• Finish the first iteration of the main menu, to re-use components for the edit menus.

[a-teammate]

Related maybe: #473 (pinning UIs on cube surfaces)

[MartinMuzatko]

Also related: #115 #363