PF 14.0: Domain Cluster does not replicate on all node

[lzammit]

Since PacketFence v14.0 when we create a domain configuration on the first node, the configuration is not replicated on the other two.

We need to go one each one of the servers to create from scratch the domain config to join them individually.

[satkunas]

@stgmsa improve PacketFence documentation to include instructions that indicate that the domain configuration is not replicated across all nodes in the cluster, and how to manually replicate this configuration.

[satkunas]

@stgmsa add domains.conf to the list of stores that are sync'd across the cluster

See https://github.com/inverse-inc/packetfence/blob/devel/bin/cluster/sync#L82

[stgmsa]

needs

1. backport
2. re-open to track the final implementation