Should be able to set p6-textarea rows

[vuongc]

Issue

• The p6-textarea tag don't have any attribute display, which led to a component smaller than his children.
  
  This can cause some issue when a form has severals field inside of it. (display: block should fix the issue).

• You can't define the textarea rows attribute.

• Default height for the row="1" (tested on browser) is way too big, it's the same with the p6-input.