Reshape window for editing of views

Rationale / Begründung

The new platform for views editing is much better than the previous one! One remaining difficulty is that source documents tend to be long, thus hiding the buttons to save, which are at the very bottom.

Affected

Managers

Minimal functionality

Either push the buttons up, or define a fixed height for the code window (but keeping the focus on the same code line upon saving).

Nice-to-have functionality

The page might be further improved by importing the functionalities of a text editor such as Atom or Notepad++ (code alignment, prettifying, tag matching, ...) or the ones by an IDE like RStudio.