Add __match_args__ to node types (#13330)

Closes #13243.

For the most part, in order to determine which fields where worth
pattern matching against, I looked at what was being displayed in the
`StrConv` class (defined in `mypy/strconv.py`). I might've missed some
fields, but for the most part all of the important ones are there.

In addition, to make pattern matching feel more natural, I re-arranged
the fields to better align with how they look in the source code. For
example, when matching against `OpExpr`, you would do:

```python
match o:
    case OpExpr(IntExpr(1), "+", IntExpr(2)):
        pass
```

instead of:

```python
match o:
    case OpExpr("+", IntExpr(1), IntExpr(2)):
        pass
```

Author: dosisod