ENH: Add option to display dtypes below column headers
#### Is your feature request related to a problem?

My feature request is not related to a problem per se, but it can help users to spot type bugs and is not visually noisy.

I wish there could be a way to change the Pandas `str` and `html` representation to show the dtypes of columns below the headers (like R's `tibble` or Julia's `DataFrame`).

#### Describe the solution you'd like

I imagine that the solution would involve setting an option, e.g. `pd.set_option("display_dtypes", True)`.

#### API breaking implications

As far as I understand, adding such option wouldn't break the API.

#### Describe alternatives you've considered

I could try to write something in this direction, but honestly I don't even know where to find the relevant source code to start. If someone could point me the direction I would be happy to try it out.
