Add validation, adaptation and halo to prediction widgets

[qin-yu]

• Fix #205
  • Fix raw2seg CLI ignoring halo in user config
  • Add halo option to both Legacy and Napari GUIs
• Start looking into #209
  • Add widget input checking mechanism for all prediction widgets in Napari GUI
  • Add adaptation in response to user input halo

Checklist

• [x] CLI: CNN Prediction
• [x] GUI: CNN Prediction
• [x] Napari: "UNet + Segmentation" & "Extra-Pred" tabs

3D Example

2D Example

[qin-yu]

3D

2D