Switch to an another JSON schema validator

[tamasfe]

Ditching verify, and using jsonschema instead would probably bring several improvements.

The original idea of using verify was to avoid looking up the positions invalid sections after validation, however it is very slow, not extensible, and I don't have time to maintain it.

Using an actually maintained validator would be an improvement already, especially if it supports resolving references. On top of that jsonschema can be up to 10000x faster (yes, indeed), and even with the additional lookups validation should be much faster.

[tamasfe]

For anyone wondering why there is no progress on this, this is blocked on Stranger6667/jsonschema#246. Taplo currently works in WASM environments which is a feature that we'll likely keep.