(DOCSP-12669): Optimise installation/upgrade instructions for the Ope… (#409)

* (DOCSP-12699): Optimise installation/upgrade instructions for the Operator

* (DOCSP-12699): add link to the reference page

* (DOCSP-12669): fix tabs

* (DOCSP-12669): separate pages for each install method

* (DOCSP-12669): copy review feedback

* (DOCSP-12669): tech review feedback

* (DOCSP-12669): tech review feedback pt 2

* (DOCSP-12669): fix warnings

Author: jwilliams-mongo

source/includes/admonitions/fact-create-service-account-namespaces.rst

@@ -1,6 +1,7 @@
 .. important::
 
-   To watch |onprem| and |k8s-mdbrscs| in a different |k8s-ns| to which 
-   you deploy the |k8s-op-short|, see :ref:`k8s-deployment-scopes` for 
-   values you must use and additional steps you might have to perform.
+   To deploy |onprem| and |k8s-mdbrscs| in a |k8s-ns| other than the one
+   where you deploy the |k8s-op-short|, see :ref:`k8s-deployment-scopes`
+   for values you must use and additional steps you might have to
+   perform.