Get all observation types

Each observation has a type that is particular to the data domain it is from - e.g. the "River Macroinvertebrate Metrics Observation" has an ID of http://environment.data.gov.uk/ecology/def/bio/RiverInvMetricsObservation and this can be used as a filter on the /observations endpoint.

To get a list of all observation types in the data, use the /observation-types endpoint, e.g. /ecology/api/v1/observation-types?skip=0&take=250