Update Gradle build system.

Highlights:
* At least JDK 11 and/or Android Studio 2020.3.1 is now required.
* Update AGP to 7.0 and Gradle to 7.2.
* Replace jcenter() repository with mavenCentral()

Known Issue:
* Currently NDK 22 can't be used to compile yet as GLSLang has compile errors.

build.gradle

@@ -3,17 +3,17 @@
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:7.0.1'
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
@@ -26,4 +26,5 @@ task clean(type: Delete) {
 
 repositories {
     google()
+    mavenCentral()
 }