Adds vSHARP model and code quality changes

[georgeyiasemis]

• vSHARP Model: Supporting both 2D and 3D. (Details: vSHARP Paper)
• 3D Reconstruction Experiments: Various additions, such as transforms, engine changes (e.g., visualization), and the addition of new metrics and losses used in the vSHARP paper.
• Project Organization: Introduces new project folders for vSHARP and the CMRxRecon challenge.
• Minor Code Quality Enhancements (e.g. Enum capitalization)
• README update