api-ref: add missing response body for groups

1. https://developer.openstack.org/api-ref/block-storage/v3/#create-group
   "Create group" should have response body, like
    {
	"group": {
		"id": "2c311e17-9daa-4229-926a-cb9e233f06b0",
		"name": "tempest-GroupsTest-Group-938181552"
	}
    }

2. https://developer.openstack.org/api-ref/block-storage/v3/#create-group-from-source
   "Create group from source" should have response body, like
    {
        "group": {
                "id": "2c311e17-9daa-4229-926a-cb9e233f06b0",
                "name": "tempest-GroupsTest-Group-938181552"
        }
    }

3. https://developer.openstack.org/api-ref/block-storage/v3/#show-group-details
   group_type in "Show group details" or "List groups with details"
   or "Create group" should be an uuid string, not object.

4. group_snapshot_id and source_group_id should be optional in the
   response of "Show group details".

Change-Id: Iea0c8f0f6fec1b8460c4ea53ed6468adbc31abf2

api-ref/source/v3/groups.inc

@@ -95,7 +95,7 @@ Request
    - group: group
    - description: description_group_false
    - availability_zone: availability_zone
-   - group_type: group_type
+   - group_type: group_type_id_2
    - volume_types: volume_types
    - name: group_name
 
@@ -105,6 +105,20 @@ Request Example
 .. literalinclude:: ./samples/group-create-request.json
    :language: javascript
 
+Response Parameters
+-------------------
+
+.. rest_parameters:: parameters.yaml
+
+   - id: group_id
+   - name: group_name
+
+Response Example
+----------------
+
+.. literalinclude:: ./samples/group-create-response.json
+   :language: javascript
+
 
 Show group details
 ~~~~~~~~~~~~~~~~~~
@@ -143,7 +157,9 @@ Response Parameters
    - description: description_group_true
    - availability_zone: availability_zone
    - created_at: created_at
-   - group_type: group_type
+   - group_type: group_type_id_2
+   - group_snapshot_id: group_snapshot_id_2
+   - source_group_id: source_group_id_2
    - volume_types: volume_types
    - id: id
    - name: group_name
@@ -196,6 +212,20 @@ Request Example
 .. literalinclude:: ./samples/group-create-from-src-request.json
    :language: javascript
 
+Response Parameters
+-------------------
+
+.. rest_parameters:: parameters.yaml
+
+   - id: group_id
+   - name: group_name
+
+Response Example
+----------------
+
+.. literalinclude:: ./samples/group-create-from-src-response.json
+   :language: javascript
+
 
 Delete group
 ~~~~~~~~~~~~
@@ -279,7 +309,9 @@ Response Parameters
    - description: description_group_true
    - availability_zone: availability_zone
    - created_at: created_at
-   - group_type: group_type
+   - group_type: group_type_id_2
+   - group_snapshot_id: group_snapshot_id_2
+   - source_group_id: source_group_id_2
    - volume_types: volume_types
    - id: group_id
    - name: name

api-ref/source/v3/parameters.yaml

@@ -1191,6 +1191,12 @@ group_snapshot_id_1:
   in: body
   required: true
   type: string
+group_snapshot_id_2:
+  description: |
+    The ID of the group snapshot.
+  in: body
+  required: false
+  type: string
 group_snapshots:
   description: |
     A collection of group snapshots.
@@ -2646,6 +2652,12 @@ source_group_id:
   in: body
   required: true
   type: string
+source_group_id_2:
+  description: |
+    The UUID of the source group.
+  in: body
+  required: false
+  type: string
 source_reference:
   description: |
     The snapshot's origin volume information.

api-ref/source/v3/samples/group-create-from-src-response.json

@@ -0,0 +1,6 @@
+{
+    "group": {
+        "id": "6f519a48-3183-46cf-a32f-41815f816666",
+        "name": "first_group"
+    }
+}