Add some use cases before release the first major release

[masesdevelopers]

Is your feature request related to a problem? Please describe.
The content of https://github.com/masesgroup/KEFCore/blob/b11cc28bdc1e2b31078ca3a717d646173c4e6d20/src/documentation/articles/usecases.md is nonexistent.

Describe the solution you'd like
Try to fill in, even only as text, some simple use cases

Describe alternatives you've considered
N/A

Additional context
N/A