feat(Former): add useFormerState hook for managing form state

src/Former/index.ts

@@ -4,3 +4,4 @@ export { FormerButtonArea } from './FormerButtonArea';
 export { FormerResolveSpecAPI } from './FormerResolveSpecAPI';
 export { FormerRestHeadSpecAPI } from './FormerRestHeadSpecAPI';
 export { FormerDialog, FormerModel, FormerPopover } from './FormerWrappers';
+export { useFormerState } from './use-former-state';