New-project templates

[tcompa]

An idea that came up (again) during last-week meetings: create project with templates. Options:

1. Blank => no dataset
2. Image to Zarr => 2 DS: Input images [type image], output [type zarr]
3. Multiplexing => image to Zarr
4. Zarr to Zarr

This requires:

• Remove automatic creation of default dataset when creating a project fractal-server#674

[jluethi]

Currently, 2 & 3 would be the same, right? Both come with 2 datasets, but option 3 will expect multiple resources.

And the workflows will be different, but I think workflow templates should be a separate part