socials: replace twitter by mastodon

[GovanifY]

Following the discussion with TheTechnician27, I replaced our main SNS from twitter to mastodon.

Don't merge yet, haven't tested if the icon looks fine, will wait on cloudflare to see

[cloudflare-pages[bot]]

Deploying pcsx2-net-www with    Cloudflare Pages

Latest commit:	9d11a7f
Status:	✅  Deploy successful!
Preview URL:	https://e6262256.pcsx2-net-www.pages.dev
Branch Preview URL:	https://mastodon.pcsx2-net-www.pages.dev

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[refractionpcsx2]

I don't wish to replace twitter, we still use it, if anything it should have the updated x.com link.