Forgot to add one `fr` to make the French locale (hopefully) work

Forgot to add `fr` here.

It took me ages to get Mastodon set up with the tests passing because
the environment variables I needed to define weren't documented and I
had to work them out one at a time.

This change adds a .env.test file, and makes it so it isn't ignored by
git. I think it makes sense for the .env.test file to be in git, since
there's nothing secret in it, but other approaches would be to have a
.env.test.sample (like the corresponding one for production), or to set
these values in a test helper, or to adapt the tests to work with
environments other than this one. I'd be happy to make these changes if
that would be preferred.

Being able to get set up and run the tests is a pretty important part of
being able to contribute to Mastodon (or your test coverage with
suffer!), so having some sort of solution like this one is vital.

Rename media to avoid exposing filename (fixes #207)

then adjust to failure later if the request fails

skip ActionCable for follow/unfollow/block events, instead clear UI from
blocked account's posts instantly if block request succeeds. Add forgotten
i18n for sensitive content

Missing lines in the French translation

🎺 https://mastodon.social/users/Pierrec/updates/100589

e

before loading new one, cache notifications API, fix missing follow button
on public profiles

Merge

silenced mode + edits

From https://github.com/doorkeeper-gem/doorkeeper-i18n/blob/master/rails/locales/fr.yml

From https://gist.github.com/qsypoq/4cf3b858ff8242ffb013

during Fan Out On Write to load less stuff into memory