Add auth hash link to task user association e-mail

Instead the current PortalLink text and link to the portal, the following texts and link with the hash should be used if the authhash functionality is enabled. (marcmittag with an additional config, or is the enabled auth hash configuration enough here?)

EN: To open the task please click on the following link:
DE: Um die Aufgabe zu öffnen klicken Sie bitte auf den folgenden Link:

https://LINK/editor/session/?authhash=HASH