Node/Service Maintenance at Cluster level

#### Feature Description

An ability to mark a node or its services as *in maintenance* while the node is down, so when the node comes back in the cluster, it is still in maintenance.

#### Use Case(s)

In real hardware systems, we sometimes face downtime on specific servers without having the ability to predict when the node will be back again.

When we know in advance that a given node will need maintenance, we use service or node maintenance to evict the node from the cluster, so when it comes back, the node is not taken into account before some checks/sync are performed.

This is especially important on systems storing data (eg: databases, filers...), where some procedures need to be applied *before* the node can serve data.

This also could be applied in case of a security issue to avoid a given node to receive traffic by marking it unhealthy (without the ability to connect to the node for instance).