Rebase kitodo-contentserver and add missing history

[stweil]

It is very important for free software projects like this one to document as much of the project history as possible. I therefore strongly suggest to rebase kitodo-contentserver on the existing history, even if there remains a gap before version 1.1.15.

[stweil]

Citation from doc/GCS_whitepaper.pdf:

Dieses Whitepaper dient als kurzes Übersichtsdokument für die Installation und den Betrieb des Goobi Content Servers. Die Softwareentwicklung fand als Zusammenarbeit zwischen dem Göttinger Digitalisierungszentrum und intranda software statt und liegt als Open Source zur freien Verwendung unter der GNU General Public License vor.

See also the discussion at kitodo/kitodo-production#498.

[stweil]

I created a new branch kcs which includes old and new history. It still needs a clarification for the license, and the old documentation files should be restored.

[stweil]

See also my comment on an issue for kitodo-production.