Add `Cache-Control` header to openstack-stored files (#20610)
Add `Cache-Control` header to openstack-stored files (#20610)

When storing files in S3, paperclip is configured with a Cache-Control header
indicating the file is immutable, however no such header was added when using
OpenStack storage.

Luckily Paperclip's fog integration makes this trivial, with a simple
`fog_file` `Cache-Control` default doing the trick.
masto-donte-com-br/mastodon,yukimochi/mastodon,MitarashiDango/mastodon,glitch-soc/mastodon,gol-cha/mastodon,yukimochi/mastodon,theoria24/mastodon,Ryanaka/mastodon,im-in-space/mastodon,glitch-soc/mastodon,im-in-space/mastodon,masto-donte-com-br/mastodon,gol-cha/mastodon,Ryanaka/mastodon,im-in-space/mastodon,gol-cha/mastodon,masto-donte-com-br/mastodon,gol-cha/mastodon,masto-donte-com-br/mastodon,glitch-soc/mastodon,maa123/mastodon,MitarashiDango/mastodon,yukimochi/mastodon,theoria24/mastodon,Ryanaka/mastodon,glitch-soc/mastodon,theoria24/mastodon,maa123/mastodon,Ryanaka/mastodon,yukimochi/mastodon,MitarashiDango/mastodon,im-in-space/mastodon,theoria24/mastodon,MitarashiDango/mastodon,maa123/mastodon,maa123/mastodon