Revert "vcl: Abstract the Windows text rendering into a TextRenderImpl descendant."

Turns out it might be easier to actually subclass only the various SalLayout's
- let's try it first, and re-introduce this code again if not.

This reverts commit 309257ddadfdc3e46506036ed81f6e0695211ebe.
vcl: Split winlayout.cxx to .cxx and .hxx.

Change-Id: I4a26842777536ce63b482a2d69524918a18b602c
windows opengl: Prepare WinLayout (and derived classes) for OpenGL.

Change-Id: Ifd18f51ac417cb3778e61f33df30daa7be6c0bf8
windows opengl: Proof-of-concept text rendering.

We don't have a method that would paint a texture with transparency yet.  We
also need to limit the size of the DIBSection exactly to what we are going to
paint, no point in creating a huge bitmap that is mostly empty (but the part
where is the text being drawn).

Change-Id: Ice0bf325743d08e19e636be73cef6aff3cde5704