Fixes #2726
Fixes #2912

This PR is the basis for a big cleanup and reorganisation of the AST.
This first step takes the file `types/src/ts-estree.ts` and splits it up in its entirety.
This file was a monolith at 1700 lines - meaning it was a pain to organise and manage, and there was no way to isolate/restrict certain things (aside from adding comments).

This PR should ultimately be a no-op - there should be no breaking changes here.
I did fix up a number of types which I found when organising files into their folders.

Whilst this PR ultimately creates more LOC, the isolation enables a few things:
- By splitting the AST into its own module, it's isolated so easier to manage / govern
- By splitting each AST node into its own folder we can cleanly document and link to individual node specs
- By grouping nodes decls by folder, it's easier to inspect the types to validate unions are correct.
    - I found a number of invalid nodes in unions in this PR which have been fixed.
- In a future PR we can:
    - Add lint rule(s) to validate unions are correct (eg ensure all `Expression` types are included in the `Expression` union).
    - Easily add documentation about the node without cluttering things up
    - Colocate fixtures/snapshots with the node specs to document the cases that we expect a node to show up
    - Colocate the conversion logic here so that it's easier to validate that the spec and the conversion logic are in sync
        - This will make it much easier to implement and maintain #1852

I'm not sure if we will want to actually use this or not.
This was just an idea I had to allow us to embed the relevant code samples directly in a `.md` file saving consumers from having to switch between the .ts file and the .md file.

We could ofc just embed the file itself, but that's not as elegant as there's the extra cruft of `export` and  `import`s.
May end up just ditching this... but it was worth putting it up for posterity.

As an� example - this script generates the following output for `ClassProperty.ts`:

```ts
interface ClassPropertyComputedName extends BaseNode {
  type: 'ClassProperty';
  key: Expression;
  computed: true;
  value: Expression | null;
  static: boolean;
  declare: boolean;
  readonly?: boolean;
  decorators?: Decorator[];
  accessibility?: "private" | "protected" | "public";
  optional?: boolean;
  definite?: boolean;
  typeAnnotation?: TSTypeAnnotation;
}

interface ClassPropertyNonComputedName extends BaseNode {
  type: 'ClassProperty';
  key: Identifier | NumberLiteral | StringLiteral;
  computed: false;
  value: Expression | null;
  static: boolean;
  declare: boolean;
  readonly?: boolean;
  decorators?: Decorator[];
  accessibility?: "private" | "protected" | "public";
  optional?: boolean;
  definite?: boolean;
  typeAnnotation?: TSTypeAnnotation;
}

type ClassProperty =
  | ClassPropertyComputedName
  | ClassPropertyNonComputedName;
```