ecm_dbus_add_activation_service() requires suffient knowledge of its
internals to use that replacing two lines with one seems silly.

In order to use it you have to know it behaves like configure_file()
(because you have to construct the file yourself), except that it also
installs it somewhere (for which you have to make sure
DBUS_SERVICES_INSTALL_DIR is defined before you use it, which is
certainly not a given for non-KDE projects). By this point, why not just
use configure_file() and install()? The DBUS_SERVICES_INSTALL_DIR
provided by KDEInstallDirs is all the magic you actually need, and if
that's explicit in the CMakeLists.txt file, it's a lot more obvious that
you should have it defined somewhere.

REVIEW: 117581

This is deliberately modelled very closely on CMake's documentation
system.  It's a hefty patch, because it involved changing all the
documentation to be in reStructuredText format.  I also cleaned up the
copyright/license statements at the same time.

Note that the find modules contain the full license, due to the fact
that ecm_use_find_module() copies them out of the ECM distribution.

"Can you please rename it to ECMDBusAddActivationService.cmake and
the contained macro to ecm_dbus_add_activation_service(), so it follows the
naming conventions in cmake (macro has the same name as the file) and ecm (all
macros have the prefix ecm)." -> Done.
Nothing to adapt in kdelibs-frameworks yet, it has its own copy for now
(I'll get rid of it at the next ECM version upgrade).