Handle object types with no geometry allowed

[Viicos]

I will probably close this PR at some point, as I think it's better to handle it as sergei said:

instead of handling the mapping as everything inside data and special casing geometry, can't we just implicitly add the data path prefix to everything so then you get a list of targets:

• geometry
• data.firstName
• data.lastName
• data.country but the end user never needs to worry about the data. prefix (of course keeping the types in mind here) the reason I'm asking this is also because you can have a second map in the form which goes to data.additionalGeometry, and that thing also needs to be pre-processed to produce geo-json

With this solution in my mind, we would just have to remove geometry if allowGeometry is False in the objecttypes API