Store active HW status in HWServer

[reyraa]

Description

At the moment we store the HWServer on a per device basis. But in practice we only consume the status of the active device. Since devices do not emit events when they change to standby status, two issues my occur

• The status of inactive devices can fall our of sync
• The status of devices can not be updated automatically.

Therefore we should resort to maintaining the status of the active device and providing the require facilities to update the status per request, e.g. from the React app.

Motivation

• Store the status of the active device on HWServer
• Remove the status from all devices
• Provide required methods on HWManager to retrieve the active device status from HWServer.
• Add unit test coverage