Remove unused Perl modules Xen::Tools and Xen::Tools::Log

Further developement of the (if any) will happen in the git branch
"xen-tools-moose" where they are still available.

Also remove the according (already disabled) tests and test
modifications from the test suite.

Also remove no the more needed build-dependency on Moose as well as
one Makefile line installing the above mentioned Perl modules.
Remove all redundant pod-inline occurrences of "=cut"

Also care that there are always two blank lines before each "=head1"
(except behind "=head1 NAME").