New container tests fail intermittently on Aarch64

[troglobit]

The new use-case tests ospf-container and container-firewall-basic fail intermittently on Aarch64 test systems. The failures result in "inconsistent container state" errors from Podman and manifest themselves as failure to create/start at least one of the containers.

Further investigation show that the speed at which configuration is done at, using any of the M2M interfaces, unearths flaws in the asynchronous way that container creation/deletion is handled in the system. When a user adds/deletes a container the actual job is enqueued to execd, which may lead to new configurations being applied before execd has completed a previous one.

This requires a redesign/simplification to ensure the M2M interfaces wait for, at least, the deletion and cleanup of containers before applying a new configuration.