TMSS-272: use improved JSONEditorField which automagically uses the pointed-to-schema for the html editor

TMSS-272: when creating/updating the DRF field method to_internal_value is called; make sure that all urls are pointing to the correct host. When getting the DRF field method to_representation is called. Make sure we massage the data such that our html json editor can handle the schema (with all refs resolved)

TMSS-272: made working example with reusable schemas. Validation works both server-side and client-side in the json-editor widget. For the json-editor widget we need to resolve absolute URL refs as a workaround

TMSS-272: modified the JSONEditorField such that it uses the  from the jsonobject itself. This implies that we should inject the proper url for the  in all our json blobs (TODO). Extended a special version of the JSONEditorField: JSONEditorSchemaField which automatically makes sure that all  point to the correct tmss host.

TMSS-272: initial version of a way to store common json schema's in a CommonSchemaTemplate model, and inject the  uri's with the base url to make them navigatable

TMSS-287: added Quantity AbstractChoice model, and used it in ResourceType to annotate each resource type with the correct quantity.

TMSS-287: upon request of the frontend team, added more test data and added some scheduled/blueprinted tasks as well. Use TMSS_UNIT_TESTING envvar to skip expensive example data setup.

TMSS-287: indicate (via environment var) that we are using the TMSSTestEnvironment during unittesting.

TMSS-286: use the RelationalHyperlinkedModelSerializer so we always get both the pk and url, and we get additional _value fields for enums

TMSS-221: Fix nested url for listing projects in a cycle when cycle name contains a space. Also allow filtering project list by cycle via url parameter.

TMSS-272: Move antenna_set, filter and station list to common json schema. antenna_set en filter combined as one (ref-)object. Issue with oneOf and ref makes station list not common yet.