[NRRPLT-7445] Implements the import_experiment() function

* [NRRPLT-7445] Implements the import_experiment() function

* [NRRPLT-7445] Fixes pylint and pep8 errors

* [NRRPLT-7445] Fixes remaining pep8 error in it.py

* [NRRPLT-7445] Adds missing folder required by the unit tests

* [NRRPLT-7445] Adds the missing value experiment-import to the key proxy-services of the Config object

* [NRRPLT-7445] Addresses code review comments: uses request.codes.ok instead of httplib.OK

Approved-by: Manos Angelidis <angelidis@fortiss.org>