This patch specifies a set of options required to build a TLS context.
The context built from those options can later on be passed to any of
the oslo.cache backends that supports TLS connections.
Depends-on: https://review.opendev.org/774120
Change-Id: I66df247543f28b4343c15f4e151231c0e100d00a
(cherry picked from commit 44fc5d25c1)