jjb: replace usage of `defaults` by `job-template`

jjb: replace usage of `defaults` by `job-template`

This seems more appropriate and allows for usage of parameters such as
`lttngversion`. We will use `lttngversion` in a following commit.

This change also renames the canary jobs are renamed such as
`vm_tests_canary` -> `vm_tests_kcanary_lcanary`. I did that to
simply the templates.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>