feat(codebuild): cache sharing of CodeBuild projects (#34257)

### Issue # (if applicable)

None

### Reason for this change

Cloudformation supports for configuring [cache namespace for CodeBuild projects](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-codebuild-project-projectcache.html#cfn-codebuild-project-projectcache-cachenamespace).

This feature is used for sharing the same cache across multiple projects.

https://docs.aws.amazon.com/codebuild/latest/userguide/caching-s3.html#caching-s3-sharing


### Description of changes

- Add `cacheNamespace` to `BucketCacheOptions`

### Describe any new or updated permissions being added

None

### Description of how you validated changes

Add both unit and integ tests.

### 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)

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

Author: badmintoncryer