Move common gradle config into convention plugins.

build-logic/plugins/src/main/java/android-constants.gradle

@@ -0,0 +1,9 @@
+ext {
+    BUILD_TOOLS_VERSION = '32.0.0'
+
+    COMPILE_SDK_VERSION = 33
+    TARGET_SDK_VERSION  = 31
+    MIN_SDK_VERSION = 21
+
+    JAVA_VERSION = JavaVersion.VERSION_1_8
+}

build-logic/plugins/src/main/java/signal-library.gradle

@@ -0,0 +1,62 @@
+plugins {
+    id 'com.android.library'
+    id 'kotlin-android'
+    id 'org.jlleitschuh.gradle.ktlint'
+    id 'android-constants'
+}
+
+android {
+    buildToolsVersion BUILD_TOOLS_VERSION
+    compileSdkVersion COMPILE_SDK_VERSION
+
+    defaultConfig {
+        minSdkVersion MIN_SDK_VERSION
+        targetSdkVersion TARGET_SDK_VERSION
+        multiDexEnabled true
+    }
+
+    compileOptions {
+        coreLibraryDesugaringEnabled true
+        sourceCompatibility JAVA_VERSION
+        targetCompatibility JAVA_VERSION
+    }
+
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+
+    lint {
+        disable 'InvalidVectorPath'
+    }
+}
+
+ktlint {
+    // Use a newer version to resolve https://github.com/JLLeitschuh/ktlint-gradle/issues/507
+    version = "0.47.1"
+}
+
+dependencies {
+    lintChecks project(':lintchecks')
+
+    coreLibraryDesugaring libs.android.tools.desugar
+
+    implementation libs.androidx.core.ktx
+    implementation libs.androidx.fragment.ktx
+    implementation libs.androidx.annotation
+    implementation libs.androidx.appcompat
+    implementation libs.rxjava3.rxandroid
+    implementation libs.rxjava3.rxjava
+    implementation libs.rxjava3.rxkotlin
+    implementation libs.androidx.multidex
+
+    implementation libs.kotlin.stdlib.jdk8
+    ktlintRuleset libs.ktlint.twitter.compose
+
+    testImplementation testLibs.junit.junit
+    testImplementation testLibs.mockito.core
+    testImplementation testLibs.mockito.android
+    testImplementation testLibs.mockito.kotlin
+    testImplementation testLibs.robolectric.robolectric
+    testImplementation testLibs.androidx.test.core
+    testImplementation testLibs.androidx.test.core.ktx
+}

build-logic/plugins/src/main/java/signal-sample-app.gradle

@@ -0,0 +1,65 @@
+plugins {
+    id 'com.android.application'
+    id 'kotlin-android'
+    id 'org.jlleitschuh.gradle.ktlint'
+    id 'android-constants'
+}
+
+android {
+    buildToolsVersion BUILD_TOOLS_VERSION
+    compileSdkVersion COMPILE_SDK_VERSION
+
+    defaultConfig {
+        versionCode 1
+        versionName "1.0"
+
+        minSdkVersion MIN_SDK_VERSION
+        targetSdkVersion TARGET_SDK_VERSION
+        multiDexEnabled true
+    }
+
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+
+    compileOptions {
+        coreLibraryDesugaringEnabled true
+        sourceCompatibility JAVA_VERSION
+        targetCompatibility JAVA_VERSION
+    }
+}
+
+ktlint {
+    // Use a newer version to resolve https://github.com/JLLeitschuh/ktlint-gradle/issues/507
+    version = "0.47.1"
+}
+
+dependencies {
+    coreLibraryDesugaring libs.android.tools.desugar
+
+    implementation project(':core-util')
+
+    coreLibraryDesugaring libs.android.tools.desugar
+
+    implementation libs.androidx.core.ktx
+    implementation libs.androidx.fragment.ktx
+    implementation libs.androidx.annotation
+    implementation libs.androidx.appcompat
+    implementation libs.rxjava3.rxandroid
+    implementation libs.rxjava3.rxjava
+    implementation libs.rxjava3.rxkotlin
+    implementation libs.androidx.multidex
+    implementation libs.material.material
+    implementation libs.androidx.constraintlayout
+
+    implementation libs.kotlin.stdlib.jdk8
+    ktlintRuleset libs.ktlint.twitter.compose
+
+    testImplementation testLibs.junit.junit
+    testImplementation testLibs.mockito.core
+    testImplementation testLibs.mockito.android
+    testImplementation testLibs.mockito.kotlin
+    testImplementation testLibs.robolectric.robolectric
+    testImplementation testLibs.androidx.test.core
+    testImplementation testLibs.androidx.test.core.ktx
+}