preparing separate dir for importers

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

Dockerfile

@@ -16,6 +16,9 @@ RUN cd /opt \
  && unzip occ.zip \
  && mv de.srsoftware.cal.app occ \
  && rm *.zip
+WORKDIR /opt/occ
+RUN mkdir lib/importers \
+ && cp lib/*importer*jar lib/importers/
 RUN adduser -S occ \
  && ln -s /data /home/occ/.config