Wrangle noxfile into submission

Remove noxfile
Add noxfile_config.py skipping 2.7

Author: arbrown

monitoring/snippets/v3/alerts-client/noxfile.py

@@ -22,7 +22,7 @@
 
 TEST_CONFIG_OVERRIDE = {
     # You can opt out from the test for specific Python versions.
-    'ignored_versions': [],
+    'ignored_versions': ["2.7"],
 
     # Declare optional test sessions you want to opt-in. Currently we
     # have the following optional test sessions: