Updates for iBVP Dataset and iBVPNet Model

[jnj256]

iBVP Dataset:

• Updated iBVP dataloader to support thermal video frames.
• Updated support for additional signal quality labels from second annotator (recommend to re-download the dataset for this change, if dataset is downloaded before 14-June-2024).

iBVPNet Model:

• Updated iBVPNet to take input as raw video frames, with Diff implemented within the network and correspondingly updated its trainer.
• Releasing updated pretrained model for iBVPNet trained on PURE dataset, and EfficientPhys trained on iBVP dataset

Other minor changes:

• Removed "from scipy.config import get_info" from MMPDLoader, as newer Scipy versions throw error here.
• In "CHROME_DEHAAN.py" changed 'signal.hanning' to more recently supported 'signal.windows.hann'.

[yahskapar]

Looks good to me, no requested changes from my end but please note the comment I left regarding the unsupervised_predictor.py file. It's worth double-checking functionality there.

Thanks for your contribution!