Improve indoor positioning performance and accuracy

[vkolotov]

The indoor positioning function can be improved in various ways to achieve better performance and accuracy:

• check if RSSI notification bubbles up to the binding in the most efficient way (no delays and heavy calculation)
• implement a better comparator logic (CombinedDeviceGovernorImpl) to cut out stale RSSI readings (use not only estimated distance but also time specific aspects, like device advertising periods)