Adds filtering using sensor public status (#108)

Author: esirK

sensorsafrica/api/v2/filters.py

@@ -5,6 +5,7 @@
 class CustomSensorFilter(SensorFilter):
     class Meta(SensorFilter.Meta):
         fields = {"sensor": ["exact"],
+                    "sensor__public": ["exact"],
                     "location__country": ['exact'],
                     "location__city": ['exact'],
                     "timestamp": ("gte", "lte"),