Truncate song listing for events

[Shiroizu]

Event pages that have a large amount of songs load slowly (like the Anonymous Uploading eventⅡ with ~5k entries).

One solution would be to use the same component that the artist entries use: (show top x songs).

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• Searched VocaDB/vocadb for duplicate issues.

[goomie]

Vocaloid Ps are increasingly participating in very large site-wide events like this, so it's important for these pages to be easy to use.