REF #4067
REF #4067
REF #4067
REF #4067
ref #4066 - merge branches prd-4067 and gid-4021 for better overview
ref #4066 - add the subscriptionsCtrl, fix lazy-loading initialization error, fix other minor bugs
REF #4067
ref #4066 - refactor subscriptions to subscriber, add the possibility to manage a subscribers subscriptions, other minor bug fixing
ref #4066 - code documentation
ref #4066 - add info message
ref #4066 - add info message (fix)
REF #4067
Merge branch 'master' into prd-4067-subscription

Conflicts:
	sysinfos-api/src/main/java/ch/alv/sysinfos/api/web/config/ApplicationConfig.java
	sysinfos-api/src/main/java/ch/alv/sysinfos/api/web/converter/CustomMappingJackson2HttpMessageConverter.java
	sysinfos-api/src/main/java/ch/alv/sysinfos/api/web/converter/HttpLinkFactory.java
	sysinfos-api/sysinfos-api.iml
ref #4066 - add 404-error handling
ref #4066 - add info message (refactor)
ref #4066 - add mail templates for unsubscribe
ref #4021 :construction: get system messages from the corresponding system
ref #4066 - minor changes
REF #4067
Fix deserialization of linked resources.
Fix .gitignore.