Ideas - Refactor XTF to better handle running tests in separate namespaces

[mnovak1]

Note that currently this feature is already implemented (see README.MD for more details).

However this has added extra complexity in case it's enabled by xtf.openshift.namespace.per.testcase=true as other parts of the code must take possible change of namespace into account. XTF framework was written to use single namespace and moving to namespace per test case is problematic.

Purpose of this issue is to discuss how to avoid complexity and adding extra ifs to deal with it across codebase.