Provide a custom repr for function params in `@step` decorator

I have a function like:
```
@step
def foo(x: np.ndarray, y: Dict[str, np.ndarray]): ...
```
It is marked with `@step` decorator and my problem is that the output in the allure repo is too large. I see that the special case of `represnet` is here https://github.com/allure-framework/allure-python/blob/3c74fd540021f776be7b52f8078c9d34eee5c3b6/allure-python-commons/src/utils.py#L167

So I was wondering how to handle other objects like `np.ndarray` or `Dict[str, np.ndarray]`?

One way is to subclass `dict` and give a nice `repr` to it, but what with a single numpy array?Sublassing it just so it got a better `repr` for allure looks... excessive?

Can `@step` accept an additional argument that will explicitly tell it hot to handle `obj -> str` representation?

#### I'm submitting a ...
- [x ] feature request

#### What is the current behavior?

A long text output in the allure report for types like `np.ndarray` or `Dict[str, np.ndarray]` that have long `repr`.

#### What is the expected behavior?

Make `@step` that receives explicit formatter so I can write:

```
def _my_repr(x: np.ndarray, y: Dict[str, np.ndarray]):
return format_1(x), format_2(t) # <-- custom formatting code here

@step(formatter=_my_repr)
def foo(x: np.ndarray, y: Dict[str, np.ndarray]): ...
```

#### Please tell us about your environment:

allure-pytest==2.9.45
allure-python-commons==2.9.45
pytest==6.2.5

#### Other information

I am willing on implementing that feature conditional on the fact there is a way of accepting that change to the mainstream. Will you accept a PR that parametrize `@step` in such a way?

从 allure-python-commons/src/utils.py 中的特殊情况表示逻辑开始，追踪 @step 如何收集函数参数。定义如何接受并将显式 formatter 应用于参数，然后验证 numpy 数组和字典能够生成所请求的紧凑输出，同时不改变默认行为。

由索引模型根据 Issue 内容生成。