Update and add Cloud KMS samples [(#3690)](GoogleCloudPlatform/python-docs-samples#3690)

This updates the Cloud KMS samples to match the format from the other 6
languages. It also updates the samples to note the workaround for
googleapis/gapic-generator-python#364.

Author: sethvargo

samples/snippets/README.rst

@@ -77,20 +77,6 @@ To run this sample:
     $ python quickstart.py
 
 
-Snippets
-+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-
-.. image:: https://gstatic.com/cloudssh/images/open-btn.png
-   :target: https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/GoogleCloudPlatform/python-docs-samples&page=editor&open_in_editor=kms/api-client/snippets.py,kms/api-client/README.rst
-
-
-
-
-To run this sample:
-
-.. code-block:: bash
-
-    $ python snippets.py
 
 
-.. _Google Cloud SDK: https://cloud.google.com/sdk/
+.. _Google Cloud SDK: https://cloud.google.com/sdk/

samples/snippets/README.rst.in

@@ -15,10 +15,5 @@ setup:
 samples:
 - name: Quickstart
   file: quickstart.py
-- name: Snippets
-  file: snippets.py
-  show_help: True
-- name: Asymmetric
-  file: asymmetric.py
 
 folder: kms/api-client