Add generic GameArchiveHandler game feature for non-Bethesda archive support

[LegendMaster03]

This PR adds a generic GameArchiveHandler game feature to modorganizer-uibase so game plugins can provide their own archive extraction and archive creation logic without expanding bsatk with game-specific formats.

What this adds:

• A reusable game feature interface for archive support
• Capability checks for:
• Whether a game supports a given archive
• Extracting an archive through the game plugin
• Creating an archive through the game plugin

Why:

• MO2 already has strong archive support for Bethesda titles through the existing built-in path
• Some games use archive formats that are not compatible with Bethesda BSAs even when they share a file extension
• This keeps format-specific logic in the game plugin instead of pushing unrelated format handling into bsatk

Intended use:

• Bethesda games can continue using the existing built-in archive flow
• Non-Bethesda games can expose GameArchiveHandler and have MO2 utilities delegate to that handler

Tested with:

• A downstream XnGine game plugin implementation
• MO2 2.5.2
• MO2 2.5.3-beta.2

Notes:

• This PR is only the interface layer
• Follow-up consumer PRs use this feature in modorganizer-bsa_extractor and bsapacker

[Holt59]

I'm not sure this makes sense as a game feature unless we assume depending on the game, the way we extract the same archive type changes, which I don't think it's true. This may make sense as a plugin type, with a way to access it through organizer core.

[LegendMaster03]

The use case here is that archive handling is not always determined reliably by extension alone: XnGine .BSA files are Bethesda archives, but they come from a different Bethesda engine and use a different format than the later BSA variants MO2 already supports. I used a game feature so the currently managed game can opt in only for archives it knows how to handle, without forcing the existing Bethesda archive path to guess between incompatible .BSA formats. A separate archive plugin type could also work, but I think it would still need game-scoped selection to avoid selecting the wrong handler for archives with the same extension.