[feature] make bounding box an attribute of the project

[lachlangrose]

Bounding box is used by mapdata to crop the datasets, would be good if the bounding box could be changed without requiring a new project to be built.

proj.map_data.set_bounding_box(bounding_box)
proj.map_data.load_all_map_data()

@RoyThomsonMonash if the bounding box changes and mapdata is updated, it does not seem to update the region of interest. Do the shapefiles get loaded and then cropped or is a copy stored on the object so we could change the bounding box?

I think for the proj it would be good to have a @property for bounding box and trigger any updates when the object is set.

[RoyThomsonMonash]

The raw map data is stored before it is clipped so in theory you could set the dirtyflags on all maps to True:
proj.map_data.dirtyflags = [True] * len(Datatype)
and then set the datastate to LOADED:
proj.map_data.data_states = [Datastate.LOADED] * len(Datatype)
but this is untested as a change in the bounding box during runtime was not anticipated.