[Documentation]: Rationale of To check if the CNF has multiple process types within one container: single_process_type is incorrect

[CsatariGergely]

Describe the bug
The rationale of To check if the CNF has multiple process types within one container is incorrect. Even to provide a microservice API there are processes needed.

Expected behavior
Remove the rationale and the test case.

[kosstennbl]

It is about "single_process_type" test. This test and "specialized_init_system" are cert tests, but their existence is still an ongoing debate in the community. It is possible that both of them or at least "single_process_type" would be removed somewhere in the future.
Nevertheless, I think the issue could be closed, as current documentation provides an explanation and reasoning behind this test.
Exsistance of this test is questionable and probably new issue should be opened for this discussion.

[martin-mat]

I think this issue can be open to use for further discussion about the test and its rationale.