[Gradle, JS] IR by default and report warnings for using legacy compiler

- just legacy - report warning about deprecation
- both - report warning about deprecation of legacy
- no compiler explicitly chosen - error about explicit setting compiler

warn from cli legacy compiler

nowarn flag - kotlin.js.compiler.nowarn

KT-42326
KT-53074

libraries/tools/kotlin-gradle-plugin-api/src/common/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinJsCompilerTypeHolder.kt

@@ -6,7 +6,10 @@
 package org.jetbrains.kotlin.gradle.plugin
 
 interface KotlinJsCompilerTypeHolder {
+    val compilerTypeFromProperties: KotlinJsCompilerType?
+
     val defaultJsCompilerType: KotlinJsCompilerType
+        get() = compilerTypeFromProperties ?: KotlinJsCompilerType.IR
 
     // Necessary to get rid of KotlinJsCompilerType import in build script
     val LEGACY: KotlinJsCompilerType