feat(lambda-nodejs): add bun support (#31770)

### Issue #31753

Closes #31753.

### Reason for this change

`bun` is rapidly gaining popularity because it's extremely performant compared to `node`. `bun` has its own lockfile, `bun.lockb`, which is not currently respected by AWS CDK when bundling `NodejsFunction`s.

### Description of changes

This code is very well-structured, so it was simple to add bun support alongside `yarn`, `pnpm` and `npm`.

### Description of how you validated changes

I linked this code up to a simple, sample CDK app with a `bun` lockfile. I wasn't able to `bun cdk synth` before my changes. Then, after linking up my local workspace, I was able to bundle with my `bun` lockfile.

I also added unit tests similar to those that exist for the other packages managers.

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: blimmer

packages/@aws-cdk-testing/framework-integ/test/aws-lambda-nodejs/test/integ-handlers/bun/bun.lockb

@@ -0,0 +1,6 @@
+// eslint-disable-next-line import/no-extraneous-dependencies
+import axios from 'axios';
+
+export async function handler() {
+  await axios.get('https://www.google.com');
+}