Add toggles for exporting only Solid or only non Solid LevelItem geo

[Shadowth117]

Wanted to add a way for SALVL to be able to export only visible or collision geo.

[ItsEasyActually]

This is fine after testing, but I think the names for the options in the dropdown should be modified. The naming works for great for SA2, but it's lacking for SA1/DX. A suggestion would be to set the names to:

• Only Export Visible Geometry
• Only Export Non-Visible Geometry

Keeps consistency with the way the display options already work, and is accurate for both games. A tooltip can be more in-depth on how non-visible is generally collision and visible geometry is in SA1/DX only.

Another option is using the SA2 check. In the internal salvlini variable, we have an "isSA2" bool you could use. I think it'd be fine to use that to change the option names depending on what's loaded at the time.

[pkr-sadx]

If the names are changed, the code should also be changed to check for the "Visible" flag instead because not all visible geometry is solid.