Public activities went to every inbox, so followers on an instance in
the SimplePolicy reject list still got our posts. With authorized fetch
mode on, signed fetches from those instances were also accepted, unless
the instance was in :instance, :rejected_instances too.
Check the SimplePolicy reject and accept lists for deliveries and signed
fetches, when the policy is enabled. Quarantine keeps its meaning (no
private activities). An inbox without a host no longer crashes.
Based on the Akkoma changes 90c4785b8, ca000f830, 03662501c and d2b0d8647.
Co-authored-by: FloatingGhost <hannah@coffee-and-dreams.uk>
Co-authored-by: Atsuko Karagi <atsuko.karagi@localhost>