Relocate contents of Lighting tab; hide Cloud settings when Enable clouds is disabled

[Peregrine05]

Closes #1476

Changes

• Move Sky exposure, Sky light intensity, and Apparent sky brightness to the Sky & Fog tab.
• Add an Apparent sun size control.
• Add a Sun tab.
• Move all sun controls to the Sun tab.
• Rename the Lighting tab to the Emitters tab.
• Add a hint about material emittance to the Emitters tab.
• Move ESS controls from the Advanced tab to the Emitters tab.
• Disable controls when their effects are nullified by the value of another control.
• Relocated cloud controls to a collapsible panel called Cloud settings.
• Set the panel to be hidden if Enable clouds is disabled.
• Updated some tooltips (The tooltip for Cloud Y is "Changes the height of the clouds.").
• Increase the wrapping width of the hint in the Postprocessing tab.

Disabling Controls

Sun tab:

Setting Sun Sampling Strategy:

to OFF disables:

• Sunlight Intensity

to NON_LUMINOUS disables:

• Sunlight intensity
• Sun luminosity
• Sun size
• Sunlight color

to FAST disables:

• Sun luminosity
• Sun size

to HIGH_QUALITY disables nothing.

Disabling Draw sun disables:

• Apparent sun brightness
• Apparent sun size
• Modify sun texture by color
• Apparent sun color

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Sky & Fog tab:

Setting Sky mode to BLACK disables:

• Sky exposure
• Sky light intensity
• Apparent sky brightness

Setting Fog density to 0 disables:

• Sky-fog blending

---

Emitters tab:

Disabling Enable emitters disables:

• Emitter intensity
• Emitter Sampling Strategy
• Emitter grid size
• Prevent normal emitter when using emitter sampling

Images

Sun tab:

Sky & Fog tab:

Emitters tab: