Auto-generate sample config file

This PS auto-generates the sample config file using
oslo-config-generator which is how every project should reliably
produce a config file.

In addition, the Patrole documentation was updated to link to the
generated config file, so that the documentation accurately
shows config options.

Change-Id: Ib3c39084b4c2b5a0078d1293d882cf9a9050b29b
Closes-Bug: #1709490
diff --git a/patrole_tempest_plugin/config.py b/patrole_tempest_plugin/config.py
index fcf29af..200da85 100644
--- a/patrole_tempest_plugin/config.py
+++ b/patrole_tempest_plugin/config.py
@@ -167,3 +167,18 @@
                     "'enable_reporting' is logged. This is combined with"
                     "report_log_name to generate the full path."),
 ]
+
+
+def list_opts():
+    """Return a list of oslo.config options available.
+
+    The purpose of this is to allow tools like the Oslo sample config file
+    generator to discover the options exposed to users.
+    """
+    opt_list = [
+        (patrole_group, PatroleGroup),
+        (patrole_log_group, PatroleLogGroup),
+        (rbac_group, PatroleGroup)
+    ]
+
+    return opt_list