Add Dependency Injection example and core interfaces. Implement Inject class for managing scopes and instances, along with InstanceProvider, IntegerConstantProvider, and StringConstantProvider for dependency resolution.

examples/di-example.ts

@@ -0,0 +1,3 @@
+import {DependencyManager} from '../src';
+
+const dependencyManager = new DependencyManager(async path => await import(path));