Perform automatic shutdown/stop on VM disable

Instead of requiring the VM to already be stopped, instead allow disable
state changes to perform a shutdown first. Also add a force option which
will do a hard stop instead of a shutdown.

References #148

docs/manuals/swagger.json

@@ -6680,6 +6680,12 @@
                         "required": true,
                         "type": "string"
                     },
+                    {
+                        "description": "Whether to force stop instead of shutdown VM during disable",
+                        "in": "query",
+                        "name": "force",
+                        "type": "boolean"
+                    },
                     {
                         "description": "Whether to block waiting for the state change to complete",
                         "in": "query",