Rename 2 of the status query commands

Make them more consistent with the device types.
Add getDeviceStatusCommand()

This will return a command for retrieving the status of a specified
device. The device is specified by its type name and an index which
starts from zero.
First cut LS30::Device

More to come.
Add LS30::Model::_initDevices()

Query the upstream for all configured devices, and store.