Mark features that has not been used after N days

[UnaiUribarri]

Is your feature request related to a problem? Please describe.
Retiring a feature that still has consumers reading or listening to will break that software. We need a better mechanism to identify unused features that can be retired safely.

Describe the solution you'd like
Features that has not been queried in N days and without any subscription active should be marked as unused. Retiring features that are not unused should raise a big warning.

Describe alternatives you've considered
I have read documentation and I have found no documentation about how to find if a feature is in use.

Additional context
n/a

[IrinaSouth]

Hi @UnaiUribarri,

This is a great suggestion. At this point it will require quite a bit of work as we would need to write some analytics engine, data storage integration, data analysis logic and so on...SDKs would also need to support this to push the data. We can add this item to our future roadmap, also relates and would come after this #309