Switching from Vetur to Volar for frontend dev in VSCode

[fabis94]

Vetur is old and buggy, while Volar is new and works very well. I've been trying it out for a few weeks and it works really well, but there are a few issues:

• A very basic setup seems to be more resource intensive than vetur, so we'd need to look into how to make it usable on not ultra powerful desktop machines
• It seems to have issues with TS Vue components that rely on the Vue Apollo Options API - see TheStream.vue (everything's red until you comment out the apollo key)