Change length of project name, add checks on project creation

Page: /project/create-new-project.xhtml, /project/create-new-subproject.xhtml, /project/edit-project-description.xhtml,

• Change length of project names to something longer. Perhaps 255 chars: https://gitlab.kit.edu/kit/reg-app/regapp/-/blob/main/bwreg-entities/src/main/java/edu/kit/scc/webreg/entity/project/ProjectEntity.java#L47
• Do better checks and create meaningful error messages on /project/create-new-project.xhtml . In the actual version, the checks just fail silently, leaving the user clueless, what did go wrong.
  • On length check
  • On uniqueness check for the short_name & group_name. Name of the project can be not unique.