Remove the `*` from the text of mandatory fields into code

**Is your feature request related to a problem? Please describe.**
If a field is mandatory, it's currently marked as having a `*` in [the translations string](https://github.com/code4romania/onghub/blob/main/frontend/src/assets/locales/ro/translation.json#L93).

**Describe the solution you'd like**
It would be ideal if this were an HTML attribute that gets added based on some code-level configuration.
The string can be easily edited by someone else and have the `*` removed, while it adds some unnecessary information for those working solely on the texts.