To run octavia tempest plugin some configuration need to
set in tempestconf file. If octavia service is enabled
then configuration region, enable_provider_drivers will
set automatically.
Added tripleo-ci-centos-8-scenario010-standalone job in
check and gate list.
Added tests for list_drivers and post_configuration.
Change-Id: Ic719f83f4fb9a330fc64ef46144e0b0b39c3a7d5
Signed-off-by: Amol Kahat <amolkahat@gmail.com>