ipatests: Add tests for checking available memory
The tests always force container or no container so they should
run the same in any environment.
The following cases are handled:
- container, no cgroups
- container, insufficent RAM
- container, sufficient RAM for no CA
- container, insufficient RAM with CA
- non-container, sufficient RAM
- non-container, insufficient RAM
https://pagure.io/freeipa/issue/8404
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Stanislav Levin <slev@altlinux.org>