Merge branch 'javadoc' into 'main'

...u/idatt2016/v233/SmartMat/service/group/GroupService.java

...u/idatt2016/v233/SmartMat/service/group/WasteService.java

...tt2016/v233/SmartMat/service/product/CategoryService.java

...att2016/v233/SmartMat/service/product/ProductService.java

...tt2016/v233/SmartMat/service/user/AchievementService.java

...016/v233/SmartMat/service/user/JpaUserDetailsService.java

...tnu/idatt2016/v233/SmartMat/service/user/UserService.java

.../java/ntnu/idatt2016/v233/SmartMat/util/CategoryUtil.java

...ain/java/ntnu/idatt2016/v233/SmartMat/util/GroupUtil.java

...n/java/ntnu/idatt2016/v233/SmartMat/util/ProductUtil.java

...java/ntnu/idatt2016/v233/SmartMat/util/StatisticUtil.java

...main/java/ntnu/idatt2016/v233/SmartMat/util/rsa/Jwks.java

...u/idatt2016/v233/SmartMat/util/rsa/KeyGeneratorUtils.java