Lacks OpenGL 3.3 Render Fallback for GPUs lacking Vulkan support

[Spartan322]

As needed by SS-22 and SS-111

Solved when ~godotengine/godot#58927~ godotengine/godot-proposals#8006 is solved.

[Spartan322]

Issue with support OpenGL 3.3 itself is that we use Vulkan features that aren't supported on OpenGL 3.3, such as compute shaders, such features will require detecting the "RenderingDevice" (which strangely enough "doesn't really exist" for OpenGL) and adapting the functionality for it. Most other rendering issues are likely to be shader related.

[Spartan322]

Will be solved in 4.4, see godotengine/godot#97142