Restructure contrib folder.

Restructure contrib folder.

contrib/pogen.sh -> bin/pogen.sh
bootstrap: Use new pogen location and execute it.
contrib/openvpn-tap32: Move to contrib/3rdparty/Windows/openvpn-tap32.
contrib/gnunet-logo*: Move to contrib/branding/logo/
Delete old patches in contrib, predating git.
Move buildbot data to contrib/ci/buildbot,
move docker data to contrib/ci/docker.
Create contrib/conf and populate it with config files found in contrib and bin.
Move gns related data to contrib/gns.
delete contrib/repeat.sh
Move contrib/log.php into contrib/web/log.php.
Create folder contrib/scripts and use it for most scripts in contrib.
Remove trailing whitespace in doc/Makefile.am

Signed-off-by: Nils Gillmann <ng0@n0.is>