Make the context available everywhere

[oxisto]

Currently, the translation context is nullable and we sort of expect that it’s set everywhere but it’s not.

Instead we should make the context part of the node’s constructor and make sure that all nodes (including types and scopes) set it correctly.

This is a HUGE breaking change because it involves several steps such as changing constructors, new node builders, etc. So this is something that we should aim for in 10.x