Move the implementation to a new source file in the
vcl/source/weld directory where most of the code for
implementing weld::Widget implementations is by now
(apart from the headers), while
vcl/source/window/builder.cxx is mostly about
VclBuilder.
Change-Id: Ide967dab4a5321871da057f0c6b799dbc21230dd
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/195832
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
Michael Weghorn
a28f06f474