Extended Excel Export with Creation Time, Linked Antibodies, Mouselines and Cell Lines

Reviewing the Excel export lead to mentioned extensions, optical refinement and rewriting for better extensibility. The main changes are limited to the file /literature/includes/export.php

Closes #102

The branch is already merged to the 7.x-dev branch an rolled out on the sfb-1002-dev instance.
@robert.kossen Please check if all required features are implemented properly. @hkusch

added Priority::high RDP_INF::Needs Review Urgency::medium labels

requested review from @robert.kossen

assigned to @Christian.Henke

changed the description

merged

mentioned in commit a10c1bbb