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>

libraries/push/api/build.gradle.kts

@@ -24,6 +24,7 @@ android {
 dependencies {
     implementation(libs.androidx.corektx)
     implementation(libs.coroutines.core)
+    implementation(libs.coil.compose)
     implementation(projects.libraries.matrix.api)
     implementation(projects.libraries.pushproviders.api)
 }