Completly reworked address book GUI

The addressbook itself needs a completly rework GUI as in its current form it is very hard to use it on a daily basis. It should be reworked to allow for entering all kind of information on a more uptodate state (like in Thunderbird) such that e.g. all LDIF information can be more properly be fit in.

In addition, the maintainer of that task should care about compatibility to CManager and try to use the CManager MCC instead of reinventing the wheel once again. That means, it should be first tested if CManager can replace our own addressbook implementation even if that means that work on CManager should be done instead.