[DOCS] fix tutorials for v2.0 (#422)

- Fix meta-parameter usage on tutorials.
- Install tutorial dependencies on CI.
- Switch from `requirements-test.txt` to `extras_require` for test dependencies, and also use it for tutorial dependencies.
- Make some performance tests deterministic.

python/tutorials/02-fused-softmax.py

@@ -133,7 +133,7 @@ torch.manual_seed(0)
 x = torch.randn(1823, 781, device='cuda')
 y_triton = softmax(x)
 y_torch = torch.softmax(x, axis=1)
-print(torch.allclose(y_triton, y_torch))
+assert torch.allclose(y_triton, y_torch), (y_triton, y_torch)
 
 # %%
 # As expected, the results are identical.