Update blender plugin so it can actually modify the game

[Wad67]

I spent a few days yelling at blender and messing up the game levels but now the entertainment factor has faded and someone else can deal with it.
This plugin allows you to systematically modify all the levels as much as you wish, but it is by no means a streamlined, seamless experience.
This is a comprehensive expansion of the blender plugin, which updates to blender 4.0+ and allows the following:
Reading and writing of all formats used by engine, apart from cin files.
Baking lightmaps, various methods
Awful cell grid regeneration thingy that barely works
Portal definitions, room id linking
Room id assignment on new geometry

So you can now modify the geometry of the game, assign new textures, add new entities, move entities
There are some handy buttons for entities that let you open the relevant ASL file, I started on a syntax highlighter for it and automatic linking but lost interest at some point

Animations can be loaded, modified and saved, an armature is automatically generated for groups, most animations translate in and out just fine but the more complex layering stuff is still busted. For instance the arms just don't know what to do in animations that would leave them free.

In terms of code quality, structure, etc this addon is a steaming pile of shit. I do not expect this PR to be actually merged but leaving it here for posterity in case someone seriously attempting to mod goes looking for tools or finds the original blender plugin and wonders why it is inadequate.

[Gussak]

The engine itself is really outdated, if I am not wrong, most of the rendering happends without using the GPU without shaders!

I could throw in some high poly models just to see the framerate drop tremendously, and then I created the old workaround to show icons instead of 3D models and it is just... fun. Not juicy... https://github.com/Gussak/ArxLibertatis/branches/yours

I was trying to make this wonderful game Juicy (to look good nowadays like every other Juicy games out there, because it already feels good). I really need juicy graphics to have fun, only the gameplay quality does not suffices to me.

When I perceive the task was beyond my capacity, it broke me too... :_(

I hope someone someday with passion and youth enough to join all this work will show up and bring us that juicy graphics joy xD