Error 413 when uploading large files

[MaddyGuthridge]

SvelteKit appears to have a default request filesize of 500kb or so. Find a way to increase this.

[MaddyGuthridge]

Temporary workaround in #130

A more-thorough solution would entail:

• Remove or massively increase body size limit from the node adaptor - https://svelte.dev/docs/kit/adapter-node#Environment-variables-BODY_SIZE_LIMIT
• Ensure that request bodies are not downloaded until the user is authenticated for all endpoints where large uploads are expected or possible, that way malicious unauthenticated users cannot upload large files
• Perhaps an admin-configurable upload limit