Spatial resolution cardinality

[jakubklimek]

In GeoDCAT-AP 3.0.0 revision, a discussion about the relations and cardinality of Spatial resolution on different classes (Dataset, Data Service, Distribution) was had, resulting in resolution of SEMICeu/GeoDCAT-AP#100.

It resulted in the following conclusions:

1. For Distribution, spatial resolution [0..1] represents the spatial resolution of the described file.​
2. For Data Service – spatial resolution [0..*] describes the capabilities of the data service, i.e. in which spatial resolutions it can serve data.​
3. For Dataset – spatial resolution [0..*] describes the spatial resolution of the original data in the dataset, i.e. regardless of how it is distributed using distributions.​

This is now in conflict with DCAT-AP 3.0, where for Dataset, the spatial resolution as a cardinality [0..1] (related to #372)