Refactor backend to typescript

[m9p909]

• Refactor backend to typescript so we can use objects and type checking
• Add a build step that compiles the typescript
• Rework the deployment to deploy the compiled ts

[m9p909]

Maybe use this? It's spring on the backend, so we can do architecture diagrams and make the prof happy. https://docs.nestjs.com/

I also just like it cause it's similar to angular (please don't be mad at my slightly controversial opinion that angular is good)

[m9p909]

Ok I think we agreed to do nestjs. I think we should copy the project to a new folder and set up the project there. I'm also going to migrate the backend to use the serverless framework because it's way simpler.