new packages: workrave and its dependencies (#7753)

var/spack/repos/builtin/packages/cairomm/package.py

var/spack/repos/builtin/packages/glibmm/guint16_cast.patch

var/spack/repos/builtin/packages/glibmm/package.py

var/spack/repos/builtin/packages/gtkmm/package.py

var/spack/repos/builtin/packages/libsigcpp/package.py

var/spack/repos/builtin/packages/pangomm/package.py

var/spack/repos/builtin/packages/py-cheetah/package.py

...ack/repos/builtin/packages/workrave/add_time_header.patch

...ack/repos/builtin/packages/workrave/dont_get_widget.patch

var/spack/repos/builtin/packages/workrave/no_gettext.patch

var/spack/repos/builtin/packages/workrave/package.py