ENH: add ignore_index to DataFrame / Series.sample 
#### Is your feature request related to a problem?

When sampling a dataframe / series we get the original index back by default, which is good, but we should add an option to ignore the index to keep it consistent with other methods like `drop_duplicates` and `explode` for example.
#### Describe the solution you'd like

Add `ignore_index` argument to Series/DataFrame.sample.
#### API breaking implications

None as far as I can tell.


```python
df = pd.DataFrame(
    {"col1": range(10, 20), "col2": range(20, 30), "colString": ["a"] * 10}
)
df.sample(n=3, ignore_index=True)

   col1  col2 colString
0    14    24         a
1    17    27         a
2    11    21         a
```
