Add a handler for providing evaluation context for scripts

use it on refinement.
also some refactoring on context class and around

libraries/scripting/common/src/kotlin/script/experimental/host/hostConfiguration.kt

@@ -8,6 +8,7 @@ package kotlin.script.experimental.host
 import kotlin.reflect.KClass
 import kotlin.script.experimental.api.KotlinType
 import kotlin.script.experimental.api.ScriptDependency
+import kotlin.script.experimental.api.ScriptEvaluationContextData
 import kotlin.script.experimental.util.PropertiesCollection
 
 interface ScriptingHostConfigurationKeys
@@ -52,6 +53,11 @@ val ScriptingHostConfigurationKeys.configurationDependencies by PropertiesCollec
  */
 val ScriptingHostConfigurationKeys.getScriptingClass by PropertiesCollection.key<GetScriptingClass>(isTransient = true)
 
+/**
+ * Evaluation context getter, allows to provide data to the evaluation configuration refinement functions
+ */
+val ScriptingHostConfigurationKeys.getEvaluationContext by PropertiesCollection.key<GetEvaluationContext>(isTransient = true)
+
 /**
  * The interface to the generic "class loader" for the types used in the script configurations
  */
@@ -59,6 +65,18 @@ interface GetScriptingClass {
     operator fun invoke(classType: KotlinType, contextClass: KClass<*>, hostConfiguration: ScriptingHostConfiguration): KClass<*>
 }
 
+/**
+ * A helper to enable passing lambda directly to the getEvaluationContext "keyword"
+ */
+fun ScriptingHostConfiguration.Builder.getEvaluationContext(handler: GetEvaluationContext) {
+    ScriptingHostConfiguration.getEvaluationContext.put(handler)
+}
+
+/**
+ * The interface to an evaluation context getter
+ */
+typealias GetEvaluationContext = (hostConfiguration: ScriptingHostConfiguration) -> ScriptEvaluationContextData
+
 // helper method
 fun ScriptingHostConfiguration.getScriptingClass(type: KotlinType, contextClass: KClass<*>): KClass<*> {
     val getClass = get(ScriptingHostConfiguration.getScriptingClass)