Deprecate version field and preserve order of script providers in extension point

It's impossible to guess the order of the final list when there're
providers from different vendors as they might have different versioning systems.

com.intellij.openapi.extensions.LoadingOrder constants can be used by plugins authors to
resolve priority issues.

idea/idea-core/src/org/jetbrains/kotlin/idea/core/script/gradleScriptTemplateProvider.kt

@@ -55,7 +55,6 @@ class GradleScriptTemplatesProvider(project: Project): ScriptTemplatesProvider {
     }
 
     override val id: String = "Gradle"
-    override val version: Int = 1
     override val isValid: Boolean get() = gradleExeSettings?.gradleHome != null
 
     override val templateClassNames: Iterable<String> = listOf("org.gradle.script.lang.kotlin.KotlinBuildScript")