Sometimes we have errors where we don't get a dictionary passed to
RESTObject.__init__() method. This breaks things but in confusing
ways.

Check in the __init__() method and raise an exception if it occurs.

chore: fix functional project service test

feat(objects): add support for Group wikis

Timing issues between requesting group deletion and GitLab enacting that
deletion resulted in errors while attempting to delete a user which was
the sole owner of said group (see: test_groups). Pass the 'hard_delete'
parameter to ensure user deletion.

Was incorrectly using the issue 'id' vs 'iid'.

Deploy tokens would remain in the instance if the respective project or
group was deleted without explicitly revoking the deploy tokens first.

This is a feature added in 3.8, removing it allows for the test to run
with lower python versions.

Additionally updates token creation to make use of `first_or_create()`,
to avoid errors from the script caused by GitLab constraints preventing
duplicate tokens with the same value.