Allow widgets to completely define the template

| Q                    | A
| -------------------- | ---
| Bug fix?             | N
| New feature?         | N
| BC breaks?           | ?
| CI currently passes? | ?
| Tests pass?          | ?
| Scenarios pass?      | ?
| Checkstyle issues?   | N
| Changelog updated?   | N
| Fixed tickets        | ~
| Doc PR               | ~

This gives widgets more flexibility to customize the template and even allows not to render anything