introduce evaluation context, deprecate old interfaces

Author: khvn26

evaluation-context.ts

@@ -0,0 +1,29 @@
+export type EvaluationContext = {
+    environment?: null | EnvironmentEvaluationContext;
+    feature?:     null | FeatureEvaluationContext;
+    identity?:    null | IdentityEvaluationContext;
+    [property: string]: any;
+}
+
+export type EnvironmentEvaluationContext = {
+    api_key: string;
+    [property: string]: any;
+}
+
+export type FeatureEvaluationContext = {
+    name: string;
+    [property: string]: any;
+}
+
+export type IdentityEvaluationContext = {
+    identifier?: null | string;
+    traits?:     { [key: string]: null | TraitEvaluationContext };
+    transient?:  boolean | null;
+    [property: string]: any;
+}
+
+export type TraitEvaluationContext = {
+    transient?: boolean;
+    value:      any;
+    [property: string]: any;
+}