Remove the dependency on oslo.config

Client libraries shouldn't depend on specific configuration libraries,
since that will make it difficult for other applications to adopt the
library.

This patch replaces all oslo.config usages with dictionaries. The client
will use those as options holders and all parameters are considered
optional.

Notice that `options` was preferred instead of `**options` since this
dictionary is considered a 'config object' and not a set of optional
parameters. This will make it easier for applications using
marconiclient to hold a single, mutable instance of options to pass
around.

Partially-Implements blueprint python-marconiclient-v1

Change-Id: Ib41f2957689545f05dab19338842fd9a953f2f76
Merge "Remove the dependency on oslo.config"