Add the multiplayer save button dynamically

[Belonit]

Add the save button to the game's existing multiplayer pause menu instead of replacing the entire dialog resource. The button is created before the game initializes its UI, keeping the usual appearance and save behavior. Remove the old dialog resource and unused UI code.

• Add [Settings] ShowMPSaveGameButton in spawn.ini, defaulting to yes. Set it to no to skip adding the button and moving the abort button.
• Keep an existing save button if another extension already provides one.
• Match the existing button size and spacing, placing save after game controls and moving abort down only after the save button is successfully created.

[github-actions]

Nightly build for this pull request:

• spawner-c208d2166437cb8d7366257b4bf96738288f2120.zip
• spawner-CnCNetYR-c208d2166437cb8d7366257b4bf96738288f2120.zip
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[Metadorius]

why?

[Belonit]

why?

To add the save button without replacing the entire multiplayer options dialog resource.
This saves changes made by other mods

[Metadorius]

what changes made by other mods, specifically? I do not know of any

[Belonit]

what changes made by other mods, specifically? I do not know of any

I don’t have a specific example
The main reason is to avoid maintaining a copy of the entire dialog resource just to add one button
Allowing other changes to the resource is an additional benefit