**Problem**
All of our extensions currently are built using the dom typings. This can lead to runtime errors if you mistakenly use `window` or similar
**Fix**
Exclude the dom typings from compile. Then explicitly import the node types for `URL` and `TextEncoder`
Setup a baseline tsconfig for extensions to extend. This will help make sure thatof our built-in extensions are using the recommended settings for target and so on. it also reduces duplicated code and will make updating tsconfig settings easier
