[!215] Use dependency tracking provided by UseLatexMk.cmake

Merge branch 'use-latexmk-dependency-tracking' into 'master'

ref:staging/dune-functions dune-common switched to UseLatexMk.cmake, which
exploits the dependency tracking of latexmk. Let's use this for the
dune-functions manuals, because it allows to vastly shorten the CMakelists.txt
file.

See merge request [!215]

  [!215]: gitlab.dune-project.org/staging/dune-functions/merge_requests/215
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