Animate text input that is being translated

[alansemenov]

Text inputs (TextLine, TextArea, HtmlArea) should have a new state which will show that their value is being generated (fetched etc.):

• the input should be disabled (+ some kind of a mask/different background to show that the input is locked)
• Saga icon should be animated (we can start with having a blue circle circling around the Saga icon, this will most likely change later on)
• a tooltip over the locked input saying "<label> is being translated..."