Create maps/tiles not consistent across hazards

[jmcano-arfima]

The create_tile_set method used across the different onboarding scripts has an optional argument max_zoom defined as:

max_zoom = ( int(round(math.log2(whole_map_pixels_x / pixels_per_tile))) if max_zoom is None else max_zoom )

This causes some hazards to have fewer maps than those needed for display at all levels of zoom in the Sandbox. The colormap then disappears as the user zooms in. Not sure whether this was a stylistic choice, but it is a bit rough from an user's perspective.

Solution could be as simple as determining what is the maximum required for proper visualization and setting it as default. Obviously some maps would have to be re-created in the S3.

@devarfima @joemoorhouse