feat: new background work process

This removes all previous dependencies on RabbitMQ and the need to run separate cron and requeueing processes.

script/send_html_email.rb

@@ -43,21 +43,10 @@ end
 c = OpenSSL::SSL::SSLContext.new
 c.verify_mode = OpenSSL::SSL::VERIFY_NONE
 
-<<<<<<< Updated upstream
-Net::SMTP.start("127.0.0.1", 2525) do |smtp|
-  smtp.send_message mail.to_s, mail.from.first, mail.to.first
-end
-=======
-1000.times.map do
-  Thread.new do
-    smtp = Net::SMTP.new("77.72.7.155", 25)
-    # smtp.enable_starttls(c)
-    smtp.disable_starttls
-    smtp.start("localhost")
-    smtp.send_message mail.to_s, mail.from.first, mail.to.first
-    smtp.finish
-  end
-end.each(&:join)
->>>>>>> Stashed changes
+smtp = Net::SMTP.new("127.0.0.1", 2525)
+smtp.enable_starttls(c)
+smtp.start("localhost")
+smtp.send_message mail.to_s, mail.from.first, mail.to.first
+smtp.finish
 
 puts "Sent"