re #37 make UI compatible with new User controller API
re #28 update angular to 8.x
Frontend refactored
Error and information messages modified - correct error messages from backend are displayed and information messages are translated
Sickdays is now correctly displayed in the list of users
Corrected number of remaining sickdays in user's profile
Default settings - set minimal number of sickdays to 0
Default settings - check whether everything is filled
Default settings component translated
Added units to vacation info component
Set vacation changed to add vacation
sickday refactored to sickDay
Min values of sickdays and vacation changed to 0
Re #7475 Localization
Re #7499 User profile component implemented + refactor
Re#7531 Components are guarded against invalid users
Re #7494 Components connected to API - except profile settings and add vacation components
Re#7527 SnackBar opens if the error occurs
Re#7527 Implemented import and export files on front end
Re #7499 User profile component initialized
Refactor service structure
Re #7498 Global settings component implemented
Re#7494 Implemented edit user settings
Refactored all models
Re#7493 Finished services except xlsx service
Re#7493 Modified and tested Users service
Re#7459 Implemented first popup
Re#7470 Implemented basic table