Currently, server parameters are specific to each node. To support PM-2502, the ServerParameter class must be extended to accommodate cluster-wide parameters that will be registered with the yet-to-be-implemented synchronization mechanisms.

1. Create base validate() function
2. Define the ServerParameterScope enum type and add a scope member to ServerParameter.
3. Add generation field that is of type OID and provide getter and setter method for the member.
4. Split ServerParameterSet::_map into ServerParameterSet::_nodeParameterMap and ServerParameterSet::_clusterParameterMap
5. Update ServerParameterSet::add(), remove(), getMap(), get() methods to all support both maps.
6. Update ServerParameter constructor so that the scope can be set during instantiation and to default-initialize the generation to the nil OID.
7. Enforce that any ServerParameters that are constructed with scope set to cluster are runtime only
8. Update ServerParameter unit tests as necessary