Upgrade to Gradle 8.10, Kotlin 2.0.20, reduce warnings

orx-jvm/orx-olive/build.gradle.kts

@@ -5,7 +5,9 @@ plugins {
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions.freeCompilerArgs = listOf("-opt-in=kotlin.RequiresOptIn")
+    compilerOptions {
+        freeCompilerArgs.add("-opt-in=kotlin.RequiresOptIn")
+    }
 }
 
 tasks.test {

orx-jvm/orx-olive/src/main/kotlin/ScriptObjectLoaderJSR233.kt

@@ -5,6 +5,7 @@ import java.io.File
 import java.io.InputStream
 import java.io.Reader
 import java.net.MalformedURLException
+import java.net.URI
 import java.net.URL
 import javax.script.ScriptEngineManager