Longterm play of Task*ST and DataBackends

[pat-s]

With the addition of spatial DataBackends (DataBackendVector and DataBackendRaster) from {mlr3spatial} multiple combinations of Tasks and Backends are possible:

• Task + spatial backends
• Task*ST + non-spatial backend
• Task*ST + spatial backend

Moving forward and to simplify both usage and development, we should pick one combination as the "recommended" one and potentially issue warnings for others.

cc @be-marc

[pat-s]

Summary of todays meeting

• Focus on storing spatiotemp info in the task to be independent from the backend
• Use Task*ST and Task*ST as the main tasks for spatiotemp ML
• Eventually deprecate DataBackendVector - can also be a DataBackendDT with x and y columns