refactor: Simplify multisrc structure (#2942)

buildSrc/src/main/kotlin/lib-multisrc.gradle.kts

@@ -0,0 +1,55 @@
+plugins {
+    id("com.android.library")
+    kotlin("android")
+    id("kotlinx-serialization")
+    id("org.jmailen.kotlinter")
+}
+
+android {
+    compileSdk = AndroidConfig.compileSdk
+
+    defaultConfig {
+        minSdk = AndroidConfig.minSdk
+    }
+
+    namespace = "eu.kanade.tachiyomi.multisrc.${project.name}"
+
+    sourceSets {
+        named("main") {
+            manifest.srcFile("AndroidManifest.xml")
+            java.setSrcDirs(listOf("src"))
+            res.setSrcDirs(listOf("res"))
+            assets.setSrcDirs(listOf("assets"))
+        }
+    }
+
+    buildFeatures {
+        resValues = false
+        shaders = false
+    }
+
+    kotlinOptions {
+        freeCompilerArgs += "-opt-in=kotlinx.serialization.ExperimentalSerializationApi"
+    }
+}
+
+versionCatalogs
+    .named("libs")
+    .findBundle("common")
+    .ifPresent { common ->
+        dependencies {
+            compileOnly(common)
+        }
+    }
+
+tasks {
+    preBuild {
+        dependsOn(lintKotlin)
+    }
+
+    if (System.getenv("CI") != "true") {
+        lintKotlin {
+            dependsOn(formatKotlin)
+        }
+    }
+}