* Rewrite Atom generation from stream entries to use Ox instead of Nokogiri::Builder

StreamEntry is now limited to only statuses, which allows some optimization. Removed
extra queries on AccountsController#show. AtomSerializer instead of AtomBuilderHelper
used in AccountsController#show, StreamEntriesController#show, StreamEntryRenderer
and PubSubHubbub::DistributionWorker

PubSubHubbub::DistributionWorker moves n+1 DomainBlock query to PubSubHubbub::DeliveryWorker
instead.

All Salmon slaps that aren't based on StreamEntry still use AtomBuilderHelper and Nokogiri

* All Salmon slaps now use Ox instead of Nokogiri. No touch from status on account

We're going to want these nice helper methods, lets share them with a parent class that matches Rails 5 practices (application level abstraction)

By pushing this into a worker we can reduce the amount of time the feed manager using workers eat up a connection

make regeneration worker unique, (only schedule/execute once at a time)

must be added to the Sidekiq invokation in your systemd file

The pull queue will handle link crawling, thread resolving, and OStatus
processing. Such tasks are more likely to hang for a longer time (due to
network requests) so it is more sensible to not make the "in-house" tasks
wait for them.

Allow PuSH to distribute private toots with that condition

if account lock info was up to date, otherwise re-do the FollowService
with now updated information

in the background instead. Should fix delay where blocked person
can interact with blocker for a short time before background job
gets processed

background as well since it's a computationally expensive

Adding some rescues to workers, e.g. don't fail removal job when status can't be found in the first place (already removed)

removing web app capability from non-webapp pages