feat: Improved password security policy (#2345)

Co-authored-by: Pranav Raj S <pranav@chatwoot.com>

db/migrate/20210527173755_remove_super_admin_access_tokes.rb

@@ -0,0 +1,5 @@
+class RemoveSuperAdminAccessTokes < ActiveRecord::Migration[6.0]
+  def change
+    AccessToken.where(owner_type: 'SuperAdmin').destroy_all
+  end
+end