Refactor cukinia-tests categories

[eroussy]

Currently, the cukinia-tests package has all these categories :

PACKAGES =+ " \
    ${PN}-cluster \
    ${PN}-cluster-security \
    ${PN}-common \
    ${PN}-common-security \
    ${PN}-hypervisor \
    ${PN}-hypervisor-readonly \
    ${PN}-hypervisor-security \
    ${PN}-hypervisor-iommu \
    ${PN}-monitor \
    ${PN}-realtime \
    ${PN}-vm \
    ${PN}-update \
"

The security tests and the iommu tests must be merged in the other categories.
It has no sense to tests SEAPATH without security, and SEAPAPTH does not support the machines with no iommu.

I think it also might be relevant to remove the realtime category. These tests must be launched by hand.
This must be properly documented on https://wiki.lfenergy.org/display/SEAP/SEAPATH+Tests+and+CI