feat(cli): Get StackOutputs in CDK application

### Use Case

I have an output
```typescript
const output = new CfnOutput(this, 'BastionPublicIP', {
exportName: 'bastion-public-ip',
value: bastion.instancePublicIp,
description: 'The public IP address of the bastion host'
});
```

And I want a simple way where I can console out a message to the user for how to to connect to the bastion host, without having to write another shell script or application that has to parse the output json file.

```typescript
console.log('Use the following ssh command to connect to the bastion host:');
console.log(`ssh ec2-user@${output.value}`)
```

### Proposed Solution

Unfortunately, I am not aware of the internals of the cli, but it would seem like perhaps some form of protected callback method in the Stack or App might be provided.

There is `Stack.resolve()` but the documentation isn't clear as to what scenario it is used for.

---

This is a :rocket: Feature Request

Start by reading the CfnOutput example and the existing Stack.resolve() documentation or implementation. Investigate how the CLI currently produces the output JSON file and whether Stack or App exposes a suitable extension point. Done should provide a supported way for a CDK application to access StackOutputs and print a connection message without an external parser or script.

Written by the indexing model from the issue text.