Bug 23584: Add the controller method and tests

Bug 23584: Add the controller method and tests

This patchset adds endpoints for the patrons to change their privacy
settings regarding their guarantors.

The following endpoints are added:

  PUT /public/patrons/:patron_id/guarantors/can_see_charges
  PUT /public/patrons/:patron_id/guarantors/can_see_checkouts

They can only be used by the patron themselves with valid sessions. And
enforce the AllowPatronToSetCheckoutsVisibilityForGuarantor and
AllowPatronToSetFinesVisibilityForGuarantor system preferences when
required.

All this is covered by unit tests.

To test:
1) Run:
  $ kshell
 k$ prove t/db_dependent/api/v1/patrons.t
=> SUCCESS: Tests pass!
- Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>