Rework the wait cofirmation status shown in the admin: If there is a pending wait confirmation
request (i.e. the number of sent reminders is positive), the status is either `None` (i.e. undecided)
or `False`. Otherwise the status is `True`.
Partially reverts 2761efecaa. To handle invalid unicode characters, we now override
the LaTeX error message to remove invalid characters instead of crashing. We also
add various umlaut and invisible unicode characters to the test data.
Since access to all media content required staff login, images intended for display on the website
were no longer accessible without login. This commit removes the protection for image files of members
and startpage posts.
We also add tests to prevent this regression from happening again.
Implements the new LJP application format as outlined in #116. In particular:
- The V-32 PDF is replaced by an `.xlsx` sheet.
- The LaTeX generated PDF for the seminar report is replaced by a `.docx` file, generated by `pandoc` from a modified `.tex` file.
- The cost and participants overview from the old PDF can still be generated separately, but is no longer required.
Also adds many fields to `LJPProposal` that are required to generate the full application.
