Fix and Feature dump

[TacticalTechJay]

This PR should fix #318 and fix #317.

Along with that, it adds the following:

• approriate url for both webhooks where applicable
• meta tags and audio preview for audio files. They can't be embedded in discord.
• compression (content-encoding header) for the raw route, can be applied to the dashboard where files could be previewed.
• CORE_COMPRESSION_ENABLED, CORE_COMPRESSION_THRESHOLD, and CORE_COMPRESSION_ON_DASHBOARD variables. this will be disabled by default, Their types are boolean, human-to-byte, and boolean. on_dashboard will have compressed file previews being served on the dashboard
• some npm errors with npm i
• images resized and fitted to the preview card that's visible both on /dashboard and /files
• non-previewables having a centered height on said preview card (or what is close to center)