Renderer: Fine-tuned lighting and halo default settings

Dynamic lights are a little larger and glows/halos a little brighter.
Sky color is factored in a bit more into sector lighting.
Client: Read-only setting profiles; added "Retro" and "Enhanced"

Added two built-in renderer appearance profiles that are available
for use in read-only mode.
Fixed|UI|Client: Closed fold panel content; read-only appearance profiles in editor

When a fold panel is closed, its content is removed from the widget
tree entirely.

The editor prevents modifying read-only profiles via the GUI
(although the cvars can still be edited).