Better display of negative Timedelta
#### Code Sample, a copy-pastable example if possible

```python
In [2]: pd.to_timedelta(0, unit='ms') - pd.to_timedelta(123, unit='ms')
Out[2]: Timedelta('-1 days +23:59:59.877000')
```
#### Problem description

`Timedelta('-1 days +23:59:59.877000')` is not a very clear display of a negative `Timedelta`

It could be better (for many usages) to display negative `Timedelta` like `Timedelta('0 days -00:00:00.123000')` or `Timedelta('-0 days 00:00:00.123000')`