Rename fixtures directory to job_fixtures to prepare for adding view_fixtures
directory in the following commits.
Change-Id: Ic20997cae020b542ddc22bf444fa6b92fbcae064
This allows the use of the {% include %} tag[0] within Jinja2 templates,
with the same search path used for looking up other templates (i.e. the
one which LocalLoader is instantiated with).
[0] http://jinja.pocoo.org/docs/2.9/templates/#include
Change-Id: I0403c385ee317e1460a80a9bf717aa4712f37e2f