Split 'Standard.BruteForceByIP' into IP and Username versions

[ben-githubs]

Background

Hakmiller noticed that our Standard.BruteForceByIP rule is actually checking by username, not IP. He requested we either make the title clearer, or adjust the rule to check by IP instead. Since changing a rule's title has numerous consequences, I've instead decided to adjust the logic to check by IP, and copied the existing logic to a new rule, Standard.BruteForceByUser, so customers can keep the same behaviour if they wish.

Changes

• Title and dedup changes to Standard.BruteForceByIP
• Added new rule Standard.BruteForceByUser, which has the original logic of Standard.BruteForceByIP
• Updated standard pack to include new rule

Testing

• Titles and dedups for both rules work as expected