[HDRP] Opening a window in the wall in the first room of HDRP Template

[remi-chapelain]

Purpose of this PR

After discussing with Mathieu Muller, we had the idea of opening the main room to be able to see more the "recent" environment effects / features. (Water, Cloud Layer, Volumetric Clouds, Atmospheric Scattering, Volumetric Fog).

To be able to do that, a window has been added on the side of the main arena.

In addition to that, there's a few things that has been done to the template as well:

• Adding some water. It needed to have a water decal around the area to lower the water surface below the room 1, 2 & 3. This water decal is a procedural one (circle and rectangle together to match the template topography) lowering the surface to -10m to avoid having water in the other room. Especially if user increase the wind.
  
• Cloud Layer has been added.
• PBR Sky replaced the HDRI Sky to be able to set a ground tint cohérent with the water surface (slightly blue).
• Fog Attenuation distance has been reduced to 2000 (instead of 5000) in the main room.
• Sun rotation has been slightly changed to account for better shadows now that we have another opening in the room.
• Shadow proxy has been updated to account for the window.
• Quality settings have been modified to include water and simulation resolution according to their levels.
• Lastly, the reflection probes has been moved and tweaked a little to avoid them "leaking" into the water.

And lighting have been rebaked.

Zoom on the nice bevel because why not.

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Testing status

Opened the template with Unity 6.0, 6.1 and 6.2 to make sure nothing was broken.

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Comments to reviewers

I know there's graphic tests with this project so I need to probably updated those as well.