feat: support custom compileSdk setting (#1431)

* feat: support custom compileSdk setting
* chore: apply suggestions from code review
* chore: apply cdv-gradle-config-defaults.json suggestion
* fix: set compile sdk when null
* fix: move compileSdk null check to gradle
* fix: compile sdk requirement warning & display in gradle per subproject

Co-authored-by: Norman Breau <norman@nbsolutions.ca>

framework/build.gradle

@@ -26,6 +26,8 @@ buildscript {
         // Android Gradle Plugin (AGP) Build Tools
         classpath "com.android.tools.build:gradle:${cordovaConfig.AGP_VERSION}"
     }
+
+    cdvHelpers.verifyCordovaConfigForBuild()
 }
 
 allprojects {
@@ -42,7 +44,7 @@ allprojects {
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion cordovaConfig.SDK_VERSION
+    compileSdkVersion cordovaConfig.COMPILE_SDK_VERSION
     buildToolsVersion cordovaConfig.BUILD_TOOLS_VERSION
 
     compileOptions {