Refactor script definitions loading

Make ScriptDefinitionProvider an interface
    and provide different implementation for cli and IDEA
Rework ide extension point to a simpler interface (ScriptDefinitionContributor)
Move template loading logic into a top level function
Allow script definitions to be reloaded in IDE

compiler/tests/org/jetbrains/kotlin/cli/jvm/repl/GenericReplTest.kt

@@ -184,7 +184,7 @@ internal class TestRepl(
     private fun makeScriptDefinition(templateClasspath: List<File>, templateClassName: String): KotlinScriptDefinition {
         val classloader = URLClassLoader(templateClasspath.map { it.toURI().toURL() }.toTypedArray(), this::class.java.classLoader)
         val cls = classloader.loadClass(templateClassName)
-        return KotlinScriptDefinitionFromAnnotatedTemplate(cls.kotlin, null, null, emptyMap())
+        return KotlinScriptDefinitionFromAnnotatedTemplate(cls.kotlin, emptyMap())
     }
 
     private val scriptDef = makeScriptDefinition(templateClasspath, templateClassName)