policychecker: is allow own for me present?

policychecker: is allow own for me present?

This adds two checks which can help with detecting
config files that have no "allow own" or "check own" or "allow own_prefix"
or "check own_prefix" for services the config file is for.

This works by adding two checking rules:
1. a rule that - for a config file containing policy rule "deny own" - warns
   if the file does not contain corresponding "allow own" or "check own"
   policy rule with the same name.
2. a rule that does the same, but for 'own_prefix' instead of 'own'.

Change-Id: I758974724ffc5d5af821c44f4737ed87c9f63f59