Add U-Mamba to MONAI's network architectures

[gvk-sbs]

Adding U-Mamba to the list of MONAI's network architectures available (https://github.com/bowang-lab/U-Mamba.git) and a tutorial similar to the one provided for nnUNet - DynUNet Pipeline.

Suggested Solution:
Adapt the DynUNet tutorial pipeline to support building the U-Mamba model for a given patch-size.

Thank you!