Improvement: TextArea rows

[netbeansuser2019]

As legacy Vaadin has option to set a rows, but 10-14(+) possibly omits such feature.

Alternatively I try to use css height (includes max), but this is not so help full due to fact
that current implementations do not count well with prefix and suffix component. I mean that scrollbar is realized that way that even scroll out such prefix and suffix component.

Suggested solutions:
A) give back "rows" that target only input area for scrolling
B) give option to set height and max-height just to input area (no scrolling prefix and/or suffix
component).
C) if possible to set a flag to not scroll prefix and/or suffix component

[tomivirkki]

Related: https://github.com/vaadin/vaadin-text-field/issues/170

[web-padawan]

Closing in favor of #170 as both issues are now in the web component repo.