Remove customizations to isort formatting
We customize the display of pandas imports in setup.cfg for isort. This is documented in the contributing guide:

https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#import-formatting

To provide an example, isort would naturally order imports to be something like:

```python
from pandas.api import DataFrame
from pandas.core.dtypes.inference import is_list_like
```

Though our customization would do this:

```python
from pandas.core.dtypes.inference import is_list_like

from pandas.api import DataFrame
```

I personally have found the alphabetic rule much easier to grok and am sometimes surprised by the logic of our imports. 

Is there an actual value add to the way we do this (avoiding circular imports?) or would we consider getting rid of the customizations and just letting isort do the work

I think @jbrockmendel and @datapythonista might have some insights into historical reasoning