Caption element for table

[thevangelist]

See: https://www.w3schools.com/TAgs/tag_caption.asp

I am thinking that it should allow a React element or a string. With element you could put custom stuff inside it, or for example styling.

See WIP test screenshot:

[AllenFang]

@thevangelist, ok we will support it, thanks a lots :)

[thevangelist]

I can probably make this, as it's Hacktoberfest :)