Save device introspection in kv_store

[eddbbt]

Save device introspection in kv_store after device registration, inhibit interface deletion if device does not declare introspection during first connection

closes #391

As a breaking change, this is currently under investigation in order to decide when and where merge it

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 68.14%. Comparing base (912b5cd) to head (d43d0ad).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #946 +/- ## ========================================== + Coverage 68.04% 68.14% +0.10% ========================================== Files 281 281 Lines 7419 7431 +12 ========================================== + Hits 5048 5064 +16 + Misses 2371 2367 -4 ```

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