(WIP) feat(modal): port ServerIdentity

[aisuleep]

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Currently only allows for the changing and removing of the user's nickname and removing the server avatar. I could not figure out the uploading to autumn process, so that needs to be added to allow adding a server avatar.

Sharing in case it can be used as a base for someone else to add the avatar upload functionality.

Note: The solidjs client freezes on the server settings menu after a server avatar is added through revite. I assume this is related to the client not acknowledging server avatar changes in messages yet.

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[insertish]

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