Make size of Angular modal form specifiable

The size of Angularized modal form on Horizon is not specifiable.
So create/edit action on Angular Role panel is too wide.
This patch fixes the issue.

Change-Id: I5bd692e7e858814095e02d1c34d5f83e70d03f0f
Closes-Bug: #1743230

horizon/static/framework/widgets/form/modal-form.service.js

@@ -50,7 +50,7 @@
     function open(config) {
       var modalConfig = {
         backdrop: 'static',
-        size: 'lg',
+        size: config.size || 'lg',
         resolve: {
           context: function() {
             return {

openstack_dashboard/dashboards/identity/static/dashboard/identity/roles/actions/create.action.service.js

@@ -68,7 +68,8 @@
         title: gettext('Create Role'),
         schema: schema,
         form: ['*'],
-        model: model
+        model: model,
+        size: 'sm'
       };
       return modalFormService.open(config).then(submit);
     }

openstack_dashboard/dashboards/identity/static/dashboard/identity/roles/actions/edit.action.service.js

@@ -70,7 +70,8 @@
         title: gettext('Edit Role'),
         schema: schema,
         form: ['*'],
-        model: response.data
+        model: response.data,
+        size: 'sm'
       };
       return modalFormService.open(config).then(service.submit);
     }