Add WMI Data Provider

Sample WMI provider for those who want to see at least something at Dashboard.

- WmiDataProvider class queries remote machines via WMI directly.
- Configuration as per additional config "~/Config/WmiProviderSettings.json". Nodes list reloaded automatically when config file changed.
- There are two types of WMI queries - "static" (data which rarely changes like OS version) and "dynamic" (frquently changing metrics like CPU utilization). Each has out configurable cache timeout.
- WMI authentication uses the same config as monitoring, i.e. PollingSettings.json.
- Utilization history is stored directly in memory for two hours (as we work directly with WMI, no Orion).

Sample WmiProviderSettings.json config:
{
    nodes:  [ "localhost" ],
    StaticDataTimeoutSec: 300,
    DynamicDataTimeoutSec: 5,
    HoursToKeepHistory: 2
}