Element Call ringing notifications (#2978)

- Add `ActiveCallManager` to handle incoming and ongoing calls.
- Add ringing call notifications with full screen intents and missed call ones as part of the 'conversation' notifications.

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Co-authored-by: ElementBot <benoitm+elementbot@element.io>

tools/localazy/config.json

@@ -236,9 +236,10 @@
       ]
     },
     {
-      "name" : ":features:call",
+      "name" : ":features:call:impl",
       "includeRegex" : [
-        "call_.*"
+        "call_.*",
+        "screen_incoming_call.*"
       ]
     },
     {