Migrate from vue cli to vite

[zusorio]

This PR migrates the slmn.gg frontend from vue-cli to vite by using this guide.

The main changes are:

• Environment variables now start with VITE_ instead of VUE_APP_
• Environment variables are accessed from import.meta.env instead of process.env
• Babel was removed

[slmnio]

This looks good, I've had a play with it to try and break it and everything looks like it should be in working order. I might try to run it on the main server first, then we can merge it in completely.

[slmnio]

I used the build-stage action on the server, so dev.slmn.gg is live with it right now. It looks like Vue doesn't know that it's in developer mode, but the site does. I wonder if the stage building process can tell Vue to build in development mode so things are still accessible compared to the full prod build.

[zusorio]

I've force-enabled vue devtools in staging in 80899b54234a6cbe4aea2110c13783b9f427d625, i can take a look at fs next

[slmnio]

Nice stuff so far

[zusorio]

Recoloring works again after replacing jimp with image-js

[slmnio]

Looks great