cleanup of the presentation generation process

Clean up some bash scripts, that are used for the generation of the
presentation.

Some improvements:
* Only ssh to fsmi-login if not already running on a fsmi host.
* Use the defined postgresql service instead of manually specifing the host
* Fix bugs that could occure when having spaces in filenames
* Find the fslogo.png in the root when generating the presentation

Signed-off-by: Tobias Wiese <tobias@tobiaswiese.com>

templates/fsr_presentation.tex.j2

@@ -22,7 +22,7 @@
 \title{Fachschaftsrat Mathe/Info}
 \author{Redeleitung: {{redeleitung.name}} \\Protokoll: {{protokoll.name}} }
 \date{ {{date.strftime("%d.%m.%Y")}} }
-\logo{\includegraphics[width=17mm]{fslogo}}
+\logo{\includegraphics[width=17mm]{../../fslogo}}
 
 \begin{document}
 \begin{frame}