Add Physics 3D benchmarks

[OverloadedOrama]

Adds the following benchmarks from #36:

• 🟥CPU🟥 Area3D : Place 2000 kinematic bodies, move around 1000 Area2D nodes of different chapes. Measure performance for 10 seconds.
• 🟥CPU🟥 CharacterBody : Make a complex scene (maybe using gridmap). Throw 1000 CharacterBodies running around and jumping randomly.Measure performance for 10 seconds.
• 🟥CPU🟥 Triangle Mesh : Open a complex triangle mesh geometry collision, trow 1000 bodies on it, measure performance for 20 seconds.
• 🟥CPU🟥 SoftBody : Create a cloth softbody, throw 500 rigid bodies on it. Measure performance for 10 seconds.
• 🟪Algorithm🟪 RayCast: Measure how much it takes doing 10000 raycasts in a complex scene (lots of shapes). From random pairs of points.

🟥CPU🟥 Rigid Bodies : Throw 2000 shapes next to each other in a pit, let them solve and stack, measure performance for 20 seconds is already implemented in rigid_body_3d.gd.

Overall very similar benchmarks to #72, but in 3D. For the triangle mesh benchmark, I didn't know which mesh to use, so I used a scene made by @Erevoid and I added collisions to it. Let me know if it's complex enough.

Results on my PC

{
"benchmarks": [
{
"category": "Physics > Area 3d",
"name": "1000 Area 3d",
"results": {
"idle": 131.7,
"physics": 34.43,
"time": 0.075
}
},
{
"category": "Physics > Character Body 3d",
"name": "1000 Character Bodies 3d",
"results": {
"idle": 135.6,
"physics": 88.44,
"time": 0.134
}
},
{
"category": "Physics > Raycast 3d",
"name": "10 000 Raycast 3d",
"results": {
"time": 877.6
}
},
{
"category": "Physics > Softbody 3d",
"name": "Softbody 3d 500 Rigidbodies",
"results": {
"idle": 22.22,
"physics": 5.114,
"time": 0.085
}
},
{
"category": "Physics > Triangle Mesh",
"name": "Triangle Mesh 3d 1000 Rigidbodies",
"results": {
"idle": 61.1,
"physics": 10.85,
"time": 0.066
}
}
],
"engine": {
"version": "v4.3.beta1.official",
"version_hash": "a4f2ea91a1bd18f70a43ff4c1377db49b56bc3f0"
},
"system": {
"cpu_architecture": "x86_64",
"cpu_count": 12,
"cpu_name": "AMD Ryzen 5 1600 Six-Core Processor",
"os": "Linux"
}
}

[Calinou]

Tested locally, it works as expected.

Thanks!