Add wrapper classes for Expression types

**Is your feature request related to a problem or challenge? Please describe what you are trying to do.**

As part of the discussion in https://github.com/apache/datafusion-python/pull/1674 we found a user wants access to some of the elements within an expression. In this case, `Limit`. If there is a growing base of users who want to use `datafusion-python` to do things such as analyzing the plans and using the data in them, then we should probably add wrapper classes for each of the Expressions.

**Describe the solution you'd like**

Right now we have the expressions like `Limit` available in `datafusion.expr` reexported like

```python
Limit = expr_internal.Limit
```

Instead we could have a `datafusion.expr` module that contains

```python
class Limit(Expr):
```

which has attributes to get `fetch` and `skip`.

**Describe alternatives you've considered**

We could leave as is and continue to expose data members as requested.

**Additional context**

This is a follow on to https://github.com/apache/datafusion-python/issues/1673

Comece revisando as exportações atuais de datafusion.expr, especialmente a reexportação de expr_internal.Limit, e depois leia o PR #1674 e a issue #1673 para entender o caso de uso motivador. Defina o escopo do wrapper com base nos tipos Expression existentes; o trabalho estará concluído quando os wrappers pretendidos expuserem os dados de expressão solicitados, incluindo Limit.fetch e Limit.skip.

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