Add autogrowing text area instead of fixed input field

[ro31337]

As a user I must be able to enter multi-line text by pressing Ctrl+Enter in text input control. Text area should grow up, so I'll be able to see text lines typed. Textarea autogrowing should stop at some point, when text area height is too large (let's say about 300px).

When Enter is pressed, text should be sent, text area should be cleared and restored to it's original height.

When textarea grows, overlapping over existing chat messages is OK.