Feature: Implement missing arena progression throughout seasons

[balleny]

Describe your feature request or suggestion in detail

Setup of AZ revolves around season 8. previous seasons or progression throughout the seasons 1-7 is ignored except for 1 toggle introduced here https://github.com/azerothcore/azerothcore-wotlk/pull/16940

Describe a possible solution to your feature or suggestion in detail

a full implementation would include

• correct arena team start rating for each season (1500 til s5, 0 from s6)
• corresponding item availability and prices from pvp vendors for seasons 1-8, including the appropriate requirements to buy items in terms of rating, battleground marks and honor / arena point costs
• correct arena point calculation based on season (see https://github.com/azerothcore/azerothcore-wotlk/pull/16940)

potential other aspects.

Additional context

should be bound to Arena.ArenaSeason.ID from worldserver.config

links to item costs and requirements per season, including costs of items in season n+1 https://wowpedia.fandom.com/wiki/Season_1?oldid=2417477 https://wowpedia.fandom.com/wiki/Season_2?oldid=2175342 https://wowpedia.fandom.com/wiki/Season_3?oldid=2175343 https://wowpedia.fandom.com/wiki/Season_4?oldid=1649901 https://wowpedia.fandom.com/wiki/Season_5?oldid=1789759 https://wowpedia.fandom.com/wiki/Season_6?oldid=2176071 https://wowpedia.fandom.com/wiki/Season_7?oldid=2076854 https://wowpedia.fandom.com/wiki/Season_8?oldid=2420756

[heyitsbench]

Iirc, the other seasons are contained within the game_event table, but I'd personally prefer to see these changes behind configs rather than tied to the season ID(s), though I may be on my own on that opinion.