Add new cable model and block state generation

[kevinrpb]

Hi there!

I recently came across this mod and it's great! Big kudos!

However... Those cable blocks look funny to me (and others, #142). So here's a first approach at redesigning the model and textures to create real cables!

I'm more than anything looking for feedback on the models themselves, not so much the implementation (yet), but feel free to point out any issues or concerns 😊. I do have a couple things that need improvement (eg. caching shapes, updating state from network where we already have the 'connections'...).

Here's how the cables look:

Cheers