feat(stepper): implement reusable stepper component with navigation and validation

src/app/shared/components/stepper/step.component.scss

@@ -0,0 +1,14 @@
+.step-body {
+  animation: fadeIn 0.25s ease-out forwards;
+}
+
+@keyframes fadeIn {
+  from {
+    opacity: 0;
+    transform: translateY(8px);
+  }
+  to {
+    opacity: 1;
+    transform: translateY(0);
+  }
+}