various cleanups
A few classes have setters that are not really needed. Immutability should be treasured, so I propose to remove them.
Edited by Martin Reinecke
Beginning with 2nd June, only the "Single Sign On" option for login to the GitLab web interface will be possible. If you don't have an MPCDF wide second factor so far, please get one at our SelfService (https://selfservice.mpcdf.mpg.de). The GitLab internal second factor will not work.
A few classes have setters that are not really needed. Immutability should be treasured, so I propose to remove them.