feat: add media contribution site awards, only for non-dev community contributions

[wescopeland]

This PR adds 6 award tiers for user-submitted game screenshots.

Eligibility
The spirit of this badge is to reward community contribution, not standard dev work. A screenshot only counts towards the submitter's progress when all of the following are true:

• It was approved via the GameScreenshotModerationResource tool in Filament.
• A different user than the submitter approved it.
• The submitter has no authored achievements for that game (promoted or unpromoted, doesn't matter).
• The submitter has no active claim on that game.

Revalidation
Award eligibility is recomputed (and the badge can be downgraded or revoked) when any of these conditions change:

• A screenshot is approved in the Filament review tool.
• A user creates or drops a claim.
• A user authors an achievement for the game (becoming a dev for that game).

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