Allow flip to shhh

[lefuturiste]

Checklist

• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• This issue contains only one feature request.
• I have read and understood the contribution guidelines.
• I optionally donated to support the Fossify mission.

Feature description

Add a button that allow to ignore an incoming call, the incoming call will be still ringing (from the caller side), but the call sound will mute.
Or, like the "Flip to Shhh", detect phone flip and trigger the muting of the incoming call.

Why do you want this feature?

The "Use Flip to Shhh" allow to ignore an incoming call without giving a clue of the receiver action, it prevent the receiver of the call to deny the call which in some circonstances will indicate a clear action from the receiver (the receiver is live).

Additional information

https://www.howtogeek.com/798418/how-to-mute-calls-by-flipping-your-android-phone/

[lefuturiste]

Duplicate of #65