[PvP] Arena Team Rating progression

[balleny]

following things should be changed in worldserver config (Arena.ArenaSeason.ID)

for season <6

• Arena.LegacyArenaPoints = 0
• Arena.ArenaStartRating = 1500
• Arena.ArenaStartPersonalRating = 1500

for seasons >=6

• Arena.LegacyArenaPoints = 0
• Arena.ArenaStartRating = 0
• Arena.ArenaStartPersonalRating = 0

(potentially getting automatically solved through the merge of https://github.com/azerothcore/azerothcore-wotlk/pull/18763)

[55Honey]

Please clarify your intentions:

• <6 would be 1-5
• >=5 is 5 and beyond.

Both include 5.

[balleny]

corrected