Support the usage of suites or something to keep separated the different tests

[iblancasa]

What would you like to be added: Right now, it is possible to run a set of tests (one test per folder) but I would be nice to have more hierarchy levels. Something more similar to what we have in other testing frameworks. Also, it would be helpful is we can specify from the commandline to run one of those group of tests.

Why is this needed: It would be really nice in order to group tests that have similar functionalities. Also, it would help to have a better structure of the folders containing the tests.

[kensipe]

@iblancasa kuttl has the ability to "reuse" manifest files to support this issue. In what other ways would you like to see kuttl tests organized?