📝(react) add RHF examples

Rework a bit the recent work made on RHF example to make some component
more generic, such as RhfSelect and RhfDatepicker, which is based on a
design using RHF context hooks to provide a seamless integration.

Fixes #144

packages/react/src/components/Forms/DatePicker/stories-utils.tsx

@@ -0,0 +1,27 @@
+import { Controller, useFormContext } from "react-hook-form";
+import React from "react";
+import {
+  DatePicker,
+  DatePickerProps,
+} from ":/components/Forms/DatePicker/DatePicker";
+
+export const RhfDatePicker = (props: DatePickerProps & { name: string }) => {
+  const { control } = useFormContext();
+  return (
+    <Controller
+      control={control}
+      name={props.name}
+      render={({ field, fieldState }) => {
+        return (
+          <DatePicker
+            {...props}
+            state={fieldState.error ? "error" : "default"}
+            text={fieldState.error?.message}
+            onChange={field.onChange}
+            value={field.value}
+          />
+        );
+      }}
+    />
+  );
+};