- Directives are now separated with ";" instead of " ;",
according to https://www.w3.org/TR/CSP2/#policy-parsing
the space is optional
- Use an IO list, which at the end gets converted to a binary as
opposed to ++ing a bunch of arrays with binaries together and joining
them to a string. I doubt it gives any significant real world advantage,
but the code is cleaner and now I can sleep at night.
- The static part of csp is pre-joined to a single binary at compile time.
Same reasoning as the last point.

https://github.com/riverrun/comeonin/blob/master/UPGRADE_v5.md

The current rate limiter disable logic won't trigger when the remote ip
is not forwarded, only when the remoteip plug is not enabled, which is
not the case on most instances since it's enabled by default. This
changes the behavior to warn and disable  when the remote ip was not forwarded,
even if the RemoteIP plug is enabled.

Also closes #1620

On furher investigation it seems like all that did was cause unintuitive
behavior. The emoji request flood that was the reason for introducing it
isn't really that big of a deal either, since Plug.Static only needs to
read file modification time and size to determine the ETag.

Closes #1613

Done via the following command:
git diff fcd5dd259a --stat --name-only | xargs sed -i '/Pleroma Authors/c# Copyright © 2017-2020 Pleroma Authors <https:\/\/pleroma.social\/>'

Done via the following command:
git diff 1e6c102b --stat --name-only | cat - | xargs sed -i 's/2017-2018 Pleroma Authors/2017-2019 Pleroma Authors/'

When multiple requests are processed by rate limiter plug at the same
time and the bucket is not yet initialized, both would try to initialize
the bucket resulting in an internal server error.

It was used to check that authenticated and unauthenticated users have
different limits. Instead of sleeping a super low limit for
unauthenticated users was set, preventing them from doing 5 requests in
the first place.

Closes #1382

We didn't get rid of user info on stable yet

Closes #1382

Done via the following command:
git diff 1e6c102bfc --stat --name-only | cat - | xargs sed -i 's/2017-2018 Pleroma Authors/2017-2019 Pleroma Authors/'