Allow defining REST API with attribute tables

When Neutron APIs are implemented using its declarative attribute map
facility, allow specification of REST resource APIs in terms of those
attributes. An example table format is included in template.rst.

Change-Id: I16aa17e847295839985cd0dec1264c8f6132dcfc

specs/template.rst

@@ -159,7 +159,30 @@ Questions which need to be addressed by this section include:
 REST API impact
 ---------------
 
-Each API method which is either added or changed should have the following
+For each API resource to be implemented using Neutron's attribute map
+facility (see the neutron.api.v2.attributes), describe the resource
+collection and specify the name, type, and other essential details of
+each new or modified attribute. A table similar to the following may
+be used:
+
++----------+-------+---------+---------+------------+--------------+
+|Attribute |Type   |Access   |Default  |Validation/ |Description   |
+|Name      |       |         |Value    |Conversion  |              |
++==========+=======+=========+=========+============+==============+
+|id        |string |RO, all  |generated|N/A         |identity      |
+|          |(UUID) |         |         |            |              |
++----------+-------+---------+---------+------------+--------------+
+|name      |string |RW, all  |''       |string      |human-readable|
+|          |       |         |         |            |name          |
++----------+-------+---------+---------+------------+--------------+
+|color     |string |RW, admin|'red'    |'red',      |color         |
+|          |       |         |         |'yellow', or|indicating    |
+|          |       |         |         |'green'     |state         |
++----------+-------+---------+---------+------------+--------------+
+
+
+Each API method which is either added or changed that does not use
+Neutron's attribute map facility should have the following:
 
 * Specification for the method