feat(gpu-service): scope create forms by the selected organization

In the platform-admin "all organizations" view, add an organization picker
(the CreateOrgScopeField slot) to the SSH public key, storage type,
storage, GPU instance and instance-template create forms, placed below the
name / display-name fields. Drop the hidden owner field and let the owner
derive from the request context, matching the model-route form.

For GPU instances, scope the instance-type list to clusters the chosen org
owns (client-side, by cluster owner) so an instance can't be scheduled onto
another org's cluster; when the org owns none, show "no instance type
available" and clear the selection, cluster and CPU/memory fields. Instance
templates gain a Global level (NULL owner) and an owner tag on the card.

src/pages/gpu-service/public-keys/forms/basic.tsx

@@ -1,8 +1,8 @@
+import PluginExtraFields from '@/components/plugin-extra-fields';
 import { PageAction, validateLabelNameRegxFor63 } from '@/config';
 import { Input as CInput, Textarea, useAppUtils } from '@gpustack/core-ui';
 import { useIntl } from '@umijs/max';
 import { Form } from 'antd';
-import OwnerPrincipalIdField from '../../../_components/owner-principal-id-field';
 import { FormData } from '../config/types';
 
 const Basic = ({ action }: { action: string }) => {
@@ -11,7 +11,6 @@ const Basic = ({ action }: { action: string }) => {
 
   return (
     <>
-      <OwnerPrincipalIdField name="owner_principal_id" />
       <Form.Item<FormData>
         name="name"
         rules={[
@@ -37,6 +36,7 @@ const Basic = ({ action }: { action: string }) => {
           label={intl.formatMessage({ id: 'common.table.displayName' })}
         />
       </Form.Item>
+      <PluginExtraFields name="CreateOrgScopeField" context={{ action }} />
       <Form.Item<FormData>
         name={['spec', 'data']}
         rules={[