Fix/mark required fields

mark required fields and refactor some forms by the way

Fixes the following work packages:

* [User Story #2153](https://www.openproject.org/work_packages/2153): [Accessibility] Required fields MUST be displayed as required - group new
* [User Story #2157](https://www.openproject.org/work_packages/2157): [Accessibility] Required fields MUST be displayed as required - enumeration new
* [User Story #2162](https://www.openproject.org/work_packages/2162): [Accessibility] Required fields MUST be displayed as required - new project_type