Add user search for member add page

src/components/i18n/lang/de.json

src/components/i18n/lang/en.json

src/components/pages/GroupAddMembersPage.tsx

src/components/pages/GroupManagementPage.tsx

src/components/widgets/group/UserList.tsx

src/data/ApiRequests.ts

src/data/queries/groups.ts

src/data/schemas.ts

src/utils/utils.ts

tsconfig.json