feat: new background work process

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

db/migrate/20240213165450_create_worker_roles.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class CreateWorkerRoles < ActiveRecord::Migration[6.1]
+
+  def change
+    create_table :worker_roles do |t|
+      t.string :role
+      t.string :worker
+      t.datetime :acquired_at
+      t.index :role, unique: true
+    end
+  end
+
+end