Add option to enable admin API and quotas

This patchset adds an option which can be used to enable an
experimental admin API for Designate and quota extension for it.

Change-Id: I3c1da2a53e52a50b19a569d16e995d5e20ed3f4d
Closes-Bug: 1755451

src/config.yaml

@@ -74,3 +74,7 @@ options:
       Space delimited list of DNS servers which should be notified on every
       zone change in addition to the backend servers. List is of the form
       also_notify_ip:also_notify_port
+  enable-admin-api:
+    type: boolean
+    default: false
+    description: Enables experimental admin API for Designate.

src/templates/mitaka/designate.conf

@@ -120,11 +120,15 @@ enable_api_v2 = True
 
 # Enable Admin API (experimental)
 #enable_api_admin = False
+enable_api_admin = {{ options.enable_admin_api }}
 
 # Enabled Admin API extensions
 # Can be one or more of : reports, quotas, counts, tenants, zones
 # zone export is in zones extension
 #enabled_extensions_admin =
+{% if options.enable_admin_api -%}
+enabled_extensions_admin = reports, quotas, counts, tenants, zones
+{%- endif %}
 
 # Default per-page limit for the Admin API, a value of None means show all results
 # by default