feat: annotations REST API (#11344)

* feat(api): annotations and layers CRUD REST API

* lint

* annotations API and tests

* fix openapi spec

* fix openapi spec

* fix openapi spec

* annotations bulk delete

* fix openapi spec

* fix older tests

* fix older tests

* small lint fixes

* layer_id to pk to keep broad coherence on openapi spec

* fix openapi spec

* one more test and validation

* fix test name

* fix test

* fix bulk delete

* add name validation

* annotation uniqueness validation

* lint

* add sorting reqs and tests

* add statsd metrics

* Update superset/annotation_layers/annotations/dao.py

Co-authored-by: Ville Brofeldt <33317356+villebro@users.noreply.github.com>

* Update tests/core_tests.py

Co-authored-by: Ville Brofeldt <33317356+villebro@users.noreply.github.com>

* address comments

* address my comment :)

* fix, address comments

* lint

Co-authored-by: riahk <moar.riah@gmail.com>
Co-authored-by: Ville Brofeldt <33317356+villebro@users.noreply.github.com>

superset/annotation_layers/__init__.py

@@ -0,0 +1,16 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
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