Clarify which secret is for which unisphere in reverseproxy configmap

[jooseppi-luna]

Description

The sample secret names used in the sample reverseproxy configmap yaml are unclear. This PR makes it clear which endpoint each secret is for. There is an accompanying doc PR for this clarification here: dell/csm-docs#1370

Additionally, a few unrelated variable names were changed to comply with linting, and I added a unit test to cover the code where I changed the variable name.

GitHub Issues

GitHub Issue #
dell/csm#1568

Checklist:

• Have you run format,vet & lint checks against your submission?
• Have you made sure that the code compiles?
• Did you run the unit & integration tests successfully?
• Have you maintained at least 90% code coverage?
• Have you commented your code, particularly in hard-to-understand areas
• Have you done corresponding changes to the documentation
• Did you run tests in a real Kubernetes cluster?
• Backward compatibility is not broken

How Has This Been Tested?

Ran unit tests for both driver and reverseproxy. No integration tests run because these changes are not touched by integration tests (there are no code changes).

[abhi16394]

LGTM