SDK for email sending

something like:

```ts
import { email } from "sst/aws/email";

email.send(Resource.MyEmail, { to: "example@gmai.com", body: "..." });

email.send(Resource.MyEmail, [
  { to: "john@gmai.com", body: "..." },
  { to: "bob@gmai.com", body: "..." }
]);
```