Migrate test_minimun_basic to tempest client

Migrate the test and along with it migrate all the shared
functions used by the tests from OfficialClienTest to
ScenarioTest:
- functions related to sync and async cleanup
- create_(keypair|server|volume|sec_group|loginable_rules)
- get_remote_client

Partially implements: bp:tempest-client-scenarios
Change-Id: Idb4a1487d48af24ebcee8e7a78822b2858c1e90b
Merge "Migrate test_minimun_basic to tempest client"