Serverless function UI (#6388)

https://www.figma.com/design/xt8O9mFeLl46C5InWwoMrN/Twenty?node-id=36235-120877

Did not do the file manager part. A Function is defined using one unique
file at the moment

Feature protected by featureFlag `IS_FUNCTION_SETTINGS_ENABLED`

## Demo


https://github.com/user-attachments/assets/0acb8291-47b4-4521-a6fa-a88b9198609b

packages/twenty-front/src/pages/settings/developers/api-keys/SettingsDevelopersApiKeysNew.tsx

@@ -18,6 +18,7 @@ import { Section } from '@/ui/layout/section/components/Section';
 import { Breadcrumb } from '@/ui/navigation/bread-crumb/components/Breadcrumb';
 import { useGenerateApiKeyTokenMutation } from '~/generated/graphql';
 import { isDefined } from '~/utils/isDefined';
+import { Key } from 'ts-key-enum';
 
 export const SettingsDevelopersApiKeysNew = () => {
   const [generateOneApiKeyToken] = useGenerateApiKeyTokenMutation();
@@ -85,7 +86,7 @@ export const SettingsDevelopersApiKeysNew = () => {
             placeholder="E.g. backoffice integration"
             value={formValues.name}
             onKeyDown={(e) => {
-              if (e.key === 'Enter') {
+              if (e.key === Key.Enter) {
                 handleSave();
               }
             }}