[BUG] Series doesn't support attribute access

The `Series` doesn't support attribute access, but the [pandas'](https://pandas.pydata.org/pandas-docs/version/1.5/user_guide/indexing.html#attribute-access) can.

**To Reproduce**
```
import mars.dataframe as md
s1 = md.Series([1, 2, 3], index=list("abc"))
print(s1.b)

>>> AttributeError: 'SeriesData' object has no attribute 'b'
```

**Expected behavior**
```
>>> 2
```

Start by reproducing the Series attribute-access example from the issue and locating the Series implementation in Mars. Compare its behavior with the linked pandas attribute-access guidance; done means s1.b returns 2 for the shown input and the behavior is covered by a regression test.

Written by the indexing model from the issue text.