DynamoDB: Fix String Set and Number Set representation to CrateDB.

[surister]

Summary of the changes / Why this is an improvement

Fixes #26

Checklist

• Link to issue this PR refers to (if applicable):
• CLA is signed

[surister]

BinarySet pending

[amotl]

Excellent, thank you so much. I just added one comment where I am not sure whether it needs improvements before merging.

[surister]

I pulled out Binary and Decimal classes and just used the values from the source, we can rethink this in the future but at least now the generated SQL seems correct, please check that tests/transform/test_dynamodb.py produce correct CrateDB SQL, I think so but something could have slipped

[amotl]

Hi. In order to keep vendorized code unmodified, and code coverage at 100%, I've submitted an alternative implementation.

• DynamoDB: Fix String Set and Number Set representation to CrateDB. #29

[surister]

Closing this, because reasons..

[amotl]

Thanks a stack @surister. Just code shuffling. Credit is yours! 💯

[amotl]

Hi again. Because there might have been misunderstandings about the genesis of GH-29: It is 100% originating from this patch. I just had to hand it in separately, because I did not have access to your fork, and thus wasn't able to stack another amendment patch on top of yours.

Thanks again for submitting this improvement. It is included in relevant releases, and makes a huge difference now able to converge corresponding DynamoDB data types well.