* Change comment to better indicate setting in nginx example conf
which serves the TLP != white locations of the prodiver.
We do advertise them in the provider-metadata.json, but we still
want to use 404 to not reveal more about the directory contents.
* Make files more readable: Move ";" from variable and add it into the nginx config file.
* Add missing nginx option `disable_symlinks off;` to the tlp paths.
* Add an OpenPGP test keypair.
* Move script parts of documentation into script, so they can be used on a fresh Ubuntu 20.04 system
for within a github action to setup a csaf_provider and upload documents to it for an integration test.
* Use dineshsonachalam/markdown-autodocs in github action to automatically
insert lines from the scripts into the docs.
Co-authored-by: Bernhard Reiter <bernhard@intevation.de>