FakeVim: put (external) command out into General Messages or similar

Steps to reproduce:

• switch to FakeVim mode in Creator
• execute a command (:!CMD) which would produce lots of output, e.g.

  find -name *.cpp
  

Current behavior:

• the output is just put on a label inside a message box - end of long output is not reachable at all

Expected behavior:

• output would be put into a scrollable QPlainTextEdit on the message box or inside the General Messages of Qt Creator