chore: move all city_building from specials.json to multitile_city_buildings.json

[0Monet]

Purpose of change (The Why)

These city_building are in the wrong file.

Describe the solution (The How)

Move all city_building from specials.json to multitile_city_buildings.json

Describe alternatives you've considered

none

Testing

I created a new game before these changes and loaded it after these changes without errors.

Additional context

none

Checklist

Mandatory

• I wrote the PR title in conventional commit format.
• I ran the code formatter.
• I linked any relevant issues using github keyword syntax like closes #1234 in Summary of the PR so it can be closed automatically.
• I've committed my changes to new branch that isn't main so it won't cause conflict when updating main branch later.
• I understand that, unless specified otherwise, my contributions will fall under the AGPL v3.0 and/or CC-BY-SA 4.0 licenses