Rearrange tabs in napari

[lorenzocerrone]

Hey @qin-yu, I would like to propose the following changes.

• merge the predictions and segmentation in a single Extra workflows (to save space for the upcoming training/dataset tab)
• remove the watershed in segmentation and add back the functionalities in Main
• Always use the dropdown menu for Extra workflow (i.e., remove the TOO_MANY_WIDGES = False check). Having all the widgets open adds a lot of clutter to the UI.

[qin-yu]

• merge the predictions and segmentation in a single Extra workflows (to save space for the upcoming training/dataset tab)
• remove the watershed in segmentation and add back the functionalities in Main

These changes doesn't really affect me and might be new-user-friendly.

• Always use the dropdown menu for Extra workflow (i.e., remove the TOO_MANY_WIDGES = False check). Having all the widgets open adds a lot of clutter to the UI.

I would like to have easier access to all widgets for more direct feedback ("on_change" events) during development, I propose to have an environment variable to allow this (that's why I did a TOO_MANY_WIDGES, but didn't have time to finish)

The workflow for me to segment or to show new users how to segment using PlantSeg is the following:

1. (Add a model)
2. Load an image
3. (Gaussian blur)
4. Run prediction
5. Run watershed
6. Run filter (the one I developed)
7. Run GASP
8. Run filter
9. Export segmentation

So having "Data", "Main", and "Extra" doesn't add complexity for inference. I would say your proposal is nice overall.

[qin-yu]

Fixed by #249