Disable uploads on all wikis [DNR]

Do not revert.

prod7 is currently bordering 10% disk space remaining which leaves ~2GB space. Note this is an extremely cautious preventative action. I have decided to disable uploads to prevent the disk space going during European night hours. I *will* re enable this when I am online European morning hours so as not to create any major disruption.

The logic behind this is, if the disk space reaches 100%, services on prod7 will shutdown. prod7 currently hosts Redis, Static, DNS and the private Git repo. If these services fail, logins will fail, DNS look ups will (~50%) and Ansible will fail with the given provision of static no longer being online. Tomorrow, I will work on a long term fix whatever it is. In the mean time, if this causes any issue - feel free to mail any bulk uploads to john AT orain.org and I will be happy to process them.