build-logic: migrate Spotless to a convention plugin

build-logic/.gitignore

@@ -0,0 +1 @@
+/build

build-logic/build.gradle.kts

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+plugins { `kotlin-dsl` }
+
+dependencies { implementation(libs.build.spotless) }

build-logic/settings.gradle.kts

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+rootProject.name = "build-logic"
+
+enableFeaturePreview("VERSION_CATALOGS")
+
+pluginManagement {
+  repositories {
+    google()
+    mavenCentral()
+    gradlePluginPortal()
+  }
+}
+
+dependencyResolutionManagement {
+  repositories {
+    google()
+    mavenCentral()
+  }
+  versionCatalogs { create("libs") { from(files("../gradle/libs.versions.toml")) } }
+}
+
+rootProject.name = "build-logic"
+
+enableFeaturePreview("VERSION_CATALOGS")
+
+include("android-plugins")
+
+include("automation-plugins")
+
+include("kotlin-plugins")

build-logic/src/main/kotlin/com.github.android-password-store.spotless.gradle.kts

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+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+plugins { id("com.diffplug.spotless") }
+
+spotless {
+  kotlin {
+    ktfmt().googleStyle()
+    target("**/*.kt")
+    targetExclude("**/build/")
+  }
+  kotlinGradle {
+    ktfmt().googleStyle()
+    target("**/*.kts")
+  }
+  format("xml") {
+    target("**/*.xml")
+    targetExclude("**/build/", ".idea/")
+    trimTrailingWhitespace()
+    indentWithSpaces()
+    endWithNewline()
+  }
+}