validation
HZ
Merge branch 'develop' of https://github.com/es-stud-dp-ua/stud-portal into develop

Conflicts:
	Events/src/main/webapp/WEB-INF/views/addEvent.jsp
	Events/src/main/webapp/WEB-INF/views/editEvent.jsp
	Organisations/src/main/webapp/WEB-INF/views/addOrganisation.jsp
	Organisations/src/main/webapp/WEB-INF/views/editOrganisation.jsp