[Finished #72644102] Force ssl globally for app except in development
Merge branch 'master' into force_ssl
Merge branch 'master' of heroku.zh:pop-up-archive-staging into stream_audio_via_cdn
[#71200960] IA url construction now in AudioFile#ia_url

AudioFileUploader#url passes responsibility down to AudioFile#ia_url
when the file is stored on InternetArchive

Spec stubs AudioFile#ia_url
[#71200960] Move the IA root url into env variable