Add migration for multiplayer score links related table

[nanaya]

Just the migration because the spectator server will need to be updated to also query the new table.

Not sure if ScoreLink class name makes sense 🤔

Will be used by #10437.

Todo:

• make sure this is useful
• figure out what to do with room archival if we're going to show play history (see Lazer multiplayer room pages need to show full room history #10455)

Migrations:

• 2023_08_25_000000_create_multiplayer_score_links (just new table, should be fine run as is)
• 2023_08_25_000001_add_score_link_id_to_multiplayer_scores_high

  alter table `multiplayer_scores_high` add `score_link_id` bigint unsigned null after `score_id`
  alter table `multiplayer_scores_high` add index `top_scores_linked`(`playlist_item_id`, total_score DESC, `score_link_id`)
  

• 2023_08_25_000002_add_last_score_link_id_to_multiplayer_rooms_high

  alter table `multiplayer_rooms_high` add `last_score_link_id` bigint unsigned null after `last_score_id`
  

[notbakaneko]

seems fine 👀

[nanaya]

wait, I guess I should redate the migrations here 🤔