Find a new home for our flatpakrefs
Currently we distribute flatpakrefs via GitLab. This is not acceptable because GitLab does not set the HTTP Content-Type header to the flatpakref MIME type, so browsers open them as text files. E.g. try downloading Epiphany Tech Preview from the link at the bottom of https://webkit.org/downloads/ (which is a redirect to our GitLab instance) and you'll notice that it's a weird confusing text file, rather than a download that opens in Software.
flathub handles this way better, and we need to as well, but I don't have any ideas.
CC: @alexl