Star development info on the map

[subchannel13]

Add more star info on the galaxy map and convert star "decorators" to GUI elements.

• [x] Add GUI anchors on stars
• [ ] Convert star selector to GUI selector
• [x] Convert star name to GUI text
• [x] Add development level indicator
• [x] Add indicators for uncolonized planets
• [x] Put scene GUI elements in a layer below normal one

[subchannel13]

Selectors need significantly more work than other items on the list. They will be covered in a separate ticket.