Centralise the DI code generation logic (#3562)

* Create Anvil extension helper

* Use the helper everywhere

libraries/matrix/impl/build.gradle.kts

@@ -1,3 +1,5 @@
+import extension.setupAnvil
+
 /*
  * Copyright 2022-2024 New Vector Ltd.
  *
@@ -7,7 +9,6 @@
 
 plugins {
     id("io.element.android-library")
-    alias(libs.plugins.anvil)
     alias(libs.plugins.kotlin.serialization)
 }
 
@@ -15,9 +16,7 @@ android {
     namespace = "io.element.android.libraries.matrix.impl"
 }
 
-anvil {
-    generateDaggerFactories.set(true)
-}
+setupAnvil()
 
 dependencies {
     releaseImplementation(libs.matrix.sdk)