Similar to what is happening in Neutron, this commit renames and moves unit
test files so that they match the directory structure of the code tree.
Since the FWaaS repo's test files have imports from Neutron, there are import
changes as well, to the imports to match the Neutron test file organization.
A check script is added to monitor the test file naming and locations (to
ensure consistency).
Note: In the future the Neutron check_unit_test_structure.sh should be made
configurable, and duplicate files removed from *aaS repos.
Change-Id: I4cf1093eac88f62bbe1303233bfd37058db3821a
Closes-Bug: #1441501
96dc29350d