Migrate to nuxt3

[jojomatik]

Is your feature request related to a problem? Please describe.
This issue targets mutlitple problems:

• Rendering is fairly slow
• npm audit shows a lot of security vulnerabilities (all in dev-dependencies, so no risk for production builds)
• vue 2 is outdated, vue 3 has been around for some time now

Describe the solution you'd like
This project is migrated from vue 2 directly to nuxt 3.

Describe alternatives you've considered
Alternatively this migration could be taken in multiple steps:

1. Migrate to vue 3 and vue-cli 5
2. Migrate to nuxt 3

I do not think this is worth the work, I think if I put in the time to migrate this project I would like to do it right the first time and not only migrate to vue 3 because it is a smaller step.

Additional context
I've openend a new repository (jojomatik/nuxt-3-base) that lays out a template for a nuxt 3 app. jojomatik/nuxt-3-base#4 tracks all the issues that need to be fixed before I can start the migration on this project.