[DOCS] Add scarf to readme and docs for website analytics (#1221)

This adds a privacy notice and website analytics to the Cosmos readme
and auto-generated docs.

Note that while you cannot explicitly opt out of website analytics for
the publicly hosted readme (and docs), Scarf respects browser DND. If
that is set via the browser, telemetry for that user will not be sent to
Scarf.

Scarf privacy policy: https://about.scarf.sh/privacy-policy
Astronomer privacy policy: https://www.astronomer.io/privacy/

README.rst

@@ -77,3 +77,9 @@ License
 _______
 
 `Apache License 2.0 <https://github.com/astronomer/astronomer-cosmos/blob/main/LICENSE>`_
+
+
+Privacy Notice
+______________
+
+This project follows `Astronomer's Privacy Policy <https://www.astronomer.io/privacy/>`_

docs/index.rst

@@ -84,3 +84,13 @@ License
 _______
 
 `Apache License 2.0 <https://github.com/astronomer/astronomer-cosmos/blob/main/LICENSE>`_
+
+Privacy Notice
+______________
+
+This project follows `Astronomer's Privacy Policy <https://www.astronomer.io/privacy/>`_
+
+.. Tracking pixel for Scarf
+.. raw:: html
+
+    <img referrerpolicy="no-referrer-when-downgrade" src="https://static.scarf.sh/a.png?x-pxid=ac335a8b-a9f3-49e6-9e8e-a7ec614fb794" />