Assign BattleParties by Attackers and Standings

[ta2edchimp]

Eventually, kills from the specified system within the specified timestamp should be fetched without limiting to the BR's owner corporation.
Fetched kills should then be filtered by attackers or victims being either in the owner corporation or (to be implemented) in the owner alliance, or even have only blue standing (to be implemented, too / closes #73 and #72). That also removes the necessity to manually include blue gang members.