Manual backport of all fixes to stable/0.2

* all EDP-related stuff removed;
* auth by tenant_name and tenant_name to tenant_id convertation added;
* responses are now correctly parsed (response_key added);
* all functions that should return objects are doing it now.

Co-Authored-By: Alexander Kuznetsov <akuznetsov@mirantis.com>
Co-Authored-By: Nikita Konovalov <nkonovalov@mirantis.com>
Co-Authored-By: Sergey Galkin <sgalkin@mirantis.com>
Co-Authored-By: Yaroslav Lobankov <ylobankov@mirantis.com>

Change-Id: I8e320599780f7fc64fd1832f8c9016014c1f061c
Remove version pbr pins from setup_requires

* setuptools can never upgrade things based on setup_requires versions
* actual pbr version range should be defined in requirements.txt

Change-Id: Ia14bb4ceba874aaa2a873134efc72bc7aae0a531
(cherry picked from commit c708c90e7f7f0be343b1c7733a9ac20c1cf5aab1)
Set gerrit's defaultbranch to stable/0.2

Change-Id: I65826500830ab72cefec83c99fceafae09b6cd2d