FR: Add config for minimum confidence level

[BrunoBarroso]

Hello! great integration, loving it so far....
The thing that im missing is a setting to establish a minimum confidence level, and that it dont save snapshots that dont rank above that minimum.
Would be great if that function can be done, or instruction on how to do it via other way.

Big thanks!

[robmarkcole]

Thanks @BrunoBarroso ! This is a good FR :) Already in https://github.com/robmarkcole/HASS-Deepstack-object

• confidence: (Optional) The confidence (in %) above which detected targets are counted in the sensor state. Default value: 80

Note that the service confidence is already documented in https://docs.deepstack.cc/face-recognition/#setting-minimum-confidence