keep deploy exclude list as part of this repository

Merged username-removed-24982 requested to merge eighthave/fdroid-website:rsync-exclude-list into master

This jekyll project does not generate all parts of the website. For example, the repo itself is generated by fdroidserver. The jekyll deploy procedure should never be able to overwrite parts of the website that it does not generate. This rsync exclude list is all the parts of the website that this jekyll project does not manage.