ENH: to_latex positional argument
#### Is your feature request related to a problem?

I would like to have the possibility to specify the location of the table I'm saving, or instead of having 
```
\begin{table}
...
\end{table}
```

be able to have 
```
\begin{table}[h]
...
\end{table}
```

#### Describe the solution you'd like

I guess the solution would be to add another argument in the `to_latex` API which could take values in `(None, 'h', 'H', 'h!'...)`

#### Describe alternatives you've considered

I'm saving my tables to `.tex` files and then use the `\input{path/to/tex}` command, I did not find the possibility to give the [h] argument with input...

