feat: support UnifiedPush notifications (#749)

* build: add unified push dependency

* feat(notification): allow arbitrary push notification endpoint

* feat(notification/unified-push): show notification

* refactor(unifiedPush): use more consise null check

* feat(settings/notification): add UnifiedPush toggle

* feat(settings/notification): show no distributor message

* feat(settings/notification): disable unifiedpush when no distributor is available

* change icon name

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Co-authored-by: sk <sk22@mailbox.org>

build.gradle

@@ -3,6 +3,12 @@ buildscript {
 	repositories {
 		google()
 		mavenCentral()
+		maven {
+			url "https://www.jitpack.io"
+			content {
+				includeModule 'com.github.UnifiedPush', 'android-connector'
+			}
+		}
 	}
 	dependencies {
 		classpath 'com.android.tools.build:gradle:8.0.0'