Document the purpose of all unti test cases

[prakhya]

Although we have six test suites (Bits, chipsec, efivarfs, fwts, kernel_efi_warnings, ndctl) in LUV we have an overview of what every test suite does and some knowledge on unit tests that these six test suites launch. But it would always be useful to have a documentation that explains the purpose of each and every unit test case that these six test suites launch and what it means when the test case gets skipped/failed.

This documentation will serve developers as a quick reference to know what every test case does because it's nearly impossible to remember all and will also be very useful for users to understand their results.

[meghadey]

we have a initial draft ready. We will upload this as a wiki soon.