Java: Add basic SaaS code samples for CloudFront

[Dogiogi25]

This pull request adds code samples for new SaaS APIs in CloudFront for Javav2 SDK

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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.

[scmacdon]

I am reviewing this code

[Dogiogi25]

Regarding the main(), I was following our existing patterns here + writing them as utility-focused classes so I thought it wouldn't be necessary: https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/java_cloudfront_code_examples.html

I can add if absolutely necessary, but I don't think it's necessary for this style of code snippet + scenario

[Dogiogi25]

And thanks, a new version of the commit has been pushed with the updated import list

[tkhill-AWS]

Integration test is needed.

[Dogiogi25]

Integration test is needed.

Thanks, added in current commit, lmk if printouts or results are necessary to be shared somewhere

[scmacdon]

Cloud Desktop build and code looks good, I approve this.

[brmur]

@scmacdon WRITEME is failing with known error. Can you please address?

[scmacdon]

This PE builds the CD and code is fine.