Convert @babel/types to TS (#12431)

* babel-types flowts convert
* babel-types code generation updates
* babel-types add more generated types to src (copy logic from scripts/typescript)
* babel-types update generateBuilders to specify exact argument types
* babel-types fix deprecated types generation
* babel-types fixes
* babel-types fix potential bug
* babel-types update generateBuilders, to include proper return types
* babel-types backport types from generated index.d.ts to be included in sources
* babel-types fixes
* babel-types avoid export of builders starting with upper case in ts sources
* babel-types
* babel-types todo updates, small fixes
* babel-types generate helpers
* babel-types remove typescript definitions generation
* babel-types generate files
* babel-types copy d.ts file for deprecated ast node creators into lib folder
* babel-types use t as alias for ast node types namespace
* babel-types update generateBuilders script to use "t" as alias instead of "types"
* babel-types update deprecated builders generation to have more compact file
* babel-types publish the .d.ts file for `@babel/types`
* Publish the .d.ts file for `@babel/types`
* Fix flowcheck
* Prettier
* No need to lint generated .d.ts files (now they are generated by tsc)
* Run prepublish-prepare-dts from prepublish-build
* Fix Babel 8 tests
* Update codecov config
* babel-types more improvements
  - better type for gatherSequenceExpressions
  - mark createUnionTypeAnnotation as deprecated
  - fix createTSUnionType
  - babel-types better type for builder
  - other improvements from PR comments
* babel-types lint fix
* babel-types fix createTSUnionType
* Don't commit .d.ts file in lib, and rename "deprecated"->"uppercase" for builders
* Add back types for TS 3.7
* Update packages/babel-types/package.json
* Cleanup converters types

Co-Authored-By: Nicolò Ribaudo <nicolo.ribaudo@gmail.com>

scripts/lint-ts-typings.sh

@@ -1,6 +0,0 @@
-#!/bin/bash
-set -e
-
-tsFlags="--strict"
-
-yarn tsc $tsFlags ./packages/babel-types/lib/index.d.ts