Create configuration for latexmk

* the whole output is generated in output/
* dokumentation.{pdf,synctex.gz} are copied to project directory
* latexmk -c removes everything in output/ except from the PDF
Make makefile use latexmk
Remove dokumentation.pdf as it is not part of the template
Update gitignore

* ignore output/ instead of temporary files
Update readme
Update README: Ordnerstruktur
Merge branch 'latexmk'

fixes #9
Automatically include content/nnkapitel.tex

Uses new package.
Fixes #6.
Merge branch 'automatic-chapter-detection'

fixes #6