This moves the gulp files into the top level tsconfig project. However this also revealed that they were not being type checked and contain main errors, so I've also disabled `checkJs` for now
* Build VS Code using TS 4.4
* Remove usages of deprecated `ClientRectList`
* Add any casts for missing `caretRangeFromPoint`
* Add temporary any casts for `zoom` css propery
This non-standard css property no longer exists in lib.dom.d.ts
* MouseWheelEvent -> WheelEvent
* Pick up new TS nightly
Co-authored-by: Alexandru Dima <alexdima@microsoft.com>
Upgrades our build scripts to target ES2017 since they are run on modern versions of node
This allows us to remove shims for es6 features such as `Object.assign`, and also remove a few extra typings packages
Part of #24698
**bug**
A node_modules folder under build/lib/watch is being included in our project system. This slows down TS quite a lot
**fix**
Remove this and remove the root jsconfig.json in the project