Aperture: Start making it REUSE compliant

TODO: Add licenses for app/libs/*

Test: pipx run reuse lint
Change-Id: Id66a572d9e11ed9da2c7a922c675c3176cc44c86
diff --git a/build.gradle.kts b/build.gradle.kts
index 6e99538..35b7e49 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2022-2023 The LineageOS Project
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 plugins {
     id("com.android.application") version "7.4.2" apply false