Core/Currency: Add support of Conquest points cap for arena and bg

Remove obselete code for arena points distribution

Thanks to @Zakamurite

sql/updates/characters/2012_11_21_00_characters_worldstates_434.sql

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+UPDATE  `worldstates` SET  `comment` =  'NextCurrencyDistributionTime' WHERE `entry` =20001;

sql/updates/world/2012_11_21_00_world_command.sql

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+DELETE FROM `command` WHERE `name`='flusharenapoints';

sql/updates/world/2012_11_21_01_world_trinity_string.sql

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+DELETE FROM `trinity_string` WHERE `entry` IN ('741','742','743','744','745','746');