Makefile-tools.am: Simpler tracking of qunit make dependencies

Use a common makefile variable for qunit testing dependencies

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
dbus-test.html: Move closer to dbus.js implementation

Move dbus-test.html closer to dbus.js implementation, and also
place the dbus-test.js stuff right into dbus-test.html to follow
the model of having our QUnit tests in html files directly.

We still can't run this test directly, so it's a bit of an odd case
as it requires test-server to be running. As before we still run this
from the 'test-server --tap' test case.

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
test-journal-renderer.html: Migrate journal renderer tests to QUnit

Done a straight forward migration of the journal renderer tests
so they now run within 'make check'.

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>