Fix Build on UE 5.0.3

[guillaume-haerinck]

I have heard that an update is coming, yet it was a fun exercise to do. I hope it will help some people who want to get started with the pluggin on UE5 in the meantime 😁

What does this PR do?

fix #441, fix #440, and maybe #439

Added the macro UE_5_CONVERT in VoxelEngineVersionHelpers.h to convert some data types to the API changes (it has a cost because we are making a new object on the stack, not casting).

Used the macro UE_5_SWITCH on several places to adapt to the API changes (when needed, used a check against VOXEL_ENGINE_VERSION). As some variables are now postfixed as DEPRECATED some places will need bigger revamps in the near future.

Hide minor textures in UE5 from the Voxel details panel as they are now missing.

How was this PR tested?

Tested on UE 5.0.3 as well as UE 4.27.2 that build works. Looked for regression by using side-to-side engines (might have missed some bits as I'm a newbie user)

[Phyronnaz]

Thanks for the PR! We're indeed working on a big update internally so this won't apply to that, but I'll merge it into this repo so people can use it on 5 :)