Add nginx and systemd templates (#8770)

So they can be copied during installation instead of looking
them up in the documentation

Make default sidekiq configuration use weighted queues

Remove deprecated docs directory

config/sidekiq.yml

@@ -1,10 +1,10 @@
 ---
 :concurrency: 5
 :queues:
-  - default
-  - push
-  - mailers
-  - pull
+  - [default, 6]
+  - [push, 4]
+  - [mailers, 2]
+  - [pull]
 :schedule:
   subscriptions_scheduler:
     cron: '<%= Random.rand(0..59) %> <%= Random.rand(4..6) %> * * *'