In opencl we read and writer the profile xml with custom classes
XmlWriter and XmlWalker for reading. This classes are useful in
other places (very similar XmlWriter is used in test), so extract
the code from opencl and move it to a more common place - tools.

Refactoring of other usages will follow.

Change-Id: I8363e87b7c30083d299080adec3f99cb33ebe4cc
Reviewed-on: https://gerrit.libreoffice.org/44149Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>