Automatically re-initialize JWT from User credentials

[MBueschelberger]

When then DSMS-object is initialized with username+password, the jwt token generated expires after a given amount of time.

Then the user then wants to conitinue his/her script without the re-initialization of the dsms-object, a mechanism is needed, which automatically re-generates a new jwt from the user credentials, in case a request gives a 403.