Add MapShed Endpoint to Geoprocessing API

[rajadain]

To the geoprocessing API, add a new endpoint at /model/mapshed/, which copies the behavior of apps.modeling.views.start_mapshed.

This view should have the same decorators as all the other endpoints:

model-my-watershed/src/mmw/apps/geoprocessing_api/views.py

Lines 659 to 668 in 7a906dc

	@swagger_auto_schema(method='post',
	manual_parameters=[schemas.WKAOI],
	request_body=schemas.MULTIPOLYGON,
	responses={200: schemas.JOB_STARTED_RESPONSE})
	@decorators.api_view(['POST'])
	@decorators.authentication_classes((SessionAuthentication,
	TokenAuthentication, ))
	@decorators.permission_classes((IsAuthenticated, ))
	@decorators.throttle_classes([BurstRateThrottle, SustainedRateThrottle])
	@log_request

With the appropriate authorization header, you should be able to post a geojson to it, such as 1-sq-km.geojson.txt, or a WKAoI such as huc12__55174. In both cases, the response should be a JSON blob with a job id. This job should be queryable by the /jobs/ endpoint.

This should not include any sub-basin capability.