Squad

* Add community connector files for Google Data Studio data source.
* doc: correct errata in curl example
* api:
* restrict visibility of groups via the API
* Add all test results filtering.
* ci:
* ci/backend/lava.py: fallback `project_settings`

* api:
* fix the /builds/<id>/report API

* api:
* add schema for REST API clients.
* make api/data returns all results if the metrics is not specified.
* add endpoint for delayed reports, which are produced in the background
* ci
* lava: add option to handle lava suite
* ensure that CI test jobs are always explicitly linked to a target Build
object.
* core:
* Always create a ProjectStatus instance together with a Build one. This
solves a long-standing issue where builds that did not receive any test
results yet do not show up in the UI.
* core, frontend:
* add support specifying metric thresholds.
* add support for marking points as outliers.
* squad.core.data: fix result checking
* frontend:
* limit filtering on build page to suite names

* frontend:
* fix handling of custom templates for 404 and 401 reponses
* Merge angular apps on build page into one.
* core, frontend: implement data retention policy
* celery: log memory usage for tasks that use more than 1MB
* ci:
* fix testjobs resubmit
* api:
* gracefully handle incorrect project IDs in filters
* fix test comparison results

* frontend:
* Add Annotation line in graphs.
* Add tooltips on chart sliders.
* Add Unit tests for JS code.
* ci:
* lava: Clean up `is_pipeline` checks.
* core:
* add tracking to EmailTemplate changes

* frontend: Fix missing changes in Jinja templates