Sync apiclient and strutils from Oslo

Because of clients unification, we should reuse common
functionality from Oslo. This patch is aimed only to import classes
to the project, all the integration work will be done in a separate
patch.

Implements: blueprint common-client-library-2
Change-Id: I003b89ccc741af9933c045506c6d092b8982f8db
Reuse Resource from oslo

In the process of unification of the clients code we should
reuse common functionality from Oslo.

Related to blueprint common-client-library-2

Change-Id: Ide0bb6bcef845d5cf746d71eaed38d425403e17a
Merge "Sync apiclient and strutils from Oslo"
Merge "Reuse Resource from oslo"