Add field selector to list experiments API (#44)

* Add field selector to list experiments API

* Refactor experiment service by creating more helper functions

* Specify table fields when UI queries API for experiments list

* Fix refactoring changes

* Update experiment context to query more experiments at once

* Remove all experiment fields from required field

* Make list experiments return paginated responses when page values are not specified

* Simplify api call to list experiments to only be performed once

* Fix changes to experiment models struct

* Update treatment service with changes to experiment model struct

* Refactor pagination to only take place when fields are not specified

* Fix bug whereby query fields were not passed to experiment service

* Make api call to display number of experiments retrieve only 1 field

* Simplify API calls to list experiments endpoint

* Fix bug whereby query fields were not passed to experiment service

* Revert changes to experiments config group by modifying experiments controller behaviour

* Refactor configs and contexts

* Refactor fieldNamesSet by using imported set

api/experiments.yaml

@@ -331,6 +331,15 @@ paths:
           in: query
           schema:
             type: boolean
+        - name: fields
+          description: |
+            A selector to restrict the list of returned objects by their fields. If unset, all the fields will be returned.
+            Paginated responses will be returned if both or either of `page` and `page_size` parameters are provided.
+          in: query
+          schema:
+            type: array
+            items:
+              $ref: 'schema.yaml#/components/schemas/ExperimentField'
       responses:
         200:
           $ref: '#/components/responses/ListExperimentsSuccess'

api/schema.yaml

@@ -145,25 +145,19 @@ components:
           $ref: '#/components/schemas/SelectedTreatmentData'
         metadata:
           $ref: '#/components/schemas/SelectedTreatmentMetadata'
-    Experiment:
-      required:
-        - project_id
-        - description
-        - end_time
+    ExperimentField:
+      type: string
+      enum:
         - id
-        - interval
         - name
-        - segment
-        - start_time
-        - status
+        - type
         - status_friendly
-        - treatments
         - tier
-        - type
-        - created_at
+        - start_time
+        - end_time
         - updated_at
-        - updated_by
-        - version
+        - treatments
+    Experiment:
       type: object
       properties:
         description: