Enable Vetur/VTI typechecking

[luxaritas]

See https://vuejs.github.io/vetur/guide/vti.html

There's a fair amount of errors this spits out, so I don't have time to go after this now. However, it should be a relatively straightforward to work through them

[snehansh]

@luxaritas

I see that you have added details like:
There's a fair amount of errors this spits out..

Are you referring to errors that gets displayed in VS code in the "PROBLEMS" section when we open a .vue page in VS code.

For example, please refer screenshot below:

[luxaritas]

@snehansh Yes and no :) What I was referring to was actually running the vti command, but the errors it would raise are the same as what you should see in the problems section - it just checks the entire codebase (just like if you ran tsc --noEmit on a pure typescript codebase - you could open a file and see the errors for just that file, or run the command to get the commands across the entire codebase).

[snehansh]

@luxaritas
I am interested in working on this issue.
Please assign this to me. Thanks.

[luxaritas]

Sure, thanks! Also noting as discussed in Discord that we probably want to use vue-tsc instead as it's newer (plus vti appears to have issues)