Removed session=false qualifier from page tag in all jsp files + added authentication test in UI to show elements accordingly

Frontend

See merge request !29

Security

See merge request !28

# Conflicts:
#   gaming-sample-data/src/main/java/cz/muni/fi/pa165/sampledata/SampleDataLoadingFacadeImpl.java
#   gaming-spring-mvc/src/main/webapp/WEB-INF/tags/pagetemplate.tag

Frontend players

See merge request !27

Frontend match

See merge request !26

# Conflicts:
#	gaming-spring-mvc/src/main/webapp/WEB-INF/tags/pagetemplate.tag

Frontend ap

See merge request !25