Merge branch 'feature/120-implementation-kundenRenderer' into dev
#125 created KundengruppeCExtProvider
#125 created ComposeEMailToAllLoginsOfKundenAction and ComposeEMailToKundenDirectContactAction, which extend AbstractComposeEMailAction
#125 created dummy version of EMailTemplateChooserDialog
#125 improvements in EMailTemplateChooserDialog
#125 created email_templates.json
#125 created Template and TemplateInfo
#125 make us of Template and TemplateInfo in EMailTemplateChooserDialog and AbstractComposeEMailAction
#125 changed appearance of EMailTemplateChooserDialog
#125 changed appearance of EMailTemplateChooserDialog
#125 moved all files to an own package de.cismet.custom.mail
#120 added icons to ComposeEMailToAllLoginsOfKundenAction and ComposeEMailToKundenDirectContactAction
#125 replaced 'Template' with 'Volage in GUI (EMailTemplateChooserDialog)'