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/scripts/ScriptTemplateTest.kt

@@ -333,7 +333,7 @@ class ScriptTemplateTest : KtUsefulTestCase() {
             includeKotlinRuntime: Boolean = true
     ): Class<*>? =
             compileScriptImpl("compiler/testData/script/" + scriptPath, KotlinScriptDefinitionFromAnnotatedTemplate(
-                    scriptTemplate, null, null, environment
+                    scriptTemplate, environment
             ), runIsolated, messageCollector, includeKotlinRuntime)
 
     private fun compileScriptImpl(