Add module for dynamodb backups

[gsoria]

This PR adds a new module to handle DynamoDB backups.

Testing steps

• Create dynamodb table and a backup:

# create a table
aws dynamodb create-table \
    --table-name Music \
    --attribute-definitions \
        AttributeName=Artist,AttributeType=S \
        AttributeName=SongTitle,AttributeType=S \
    --key-schema \
        AttributeName=Artist,KeyType=HASH \
        AttributeName=SongTitle,KeyType=RANGE \
    --provisioned-throughput \
        ReadCapacityUnits=5,WriteCapacityUnits=5 \
    --table-class STANDARD

# Create backup
aws dynamodb create-backup --table-name Music --backup-name Music_backup

• Run aws-nuke including DynamoDBBackup module
• Verify if resources were cleaned up successfully

# List backups
aws dynamodb list-backups

[ekristen]

@gsoria this was implemented over on the newly promoted fork of aws-nuke which is now the successor to this one via the PR there ekristen/aws-nuke#233

Try it out. If you run into issues, report it in an issue over there.

---

Please see a copy of the notice from the README about the deprecation of this project. Sven was kind enough to grant me access to help triage and close issues and pull requests that have already been addressed in the actively maintained fork. Some additional information is located in the welcome issue for more information.

Caution

This repository for aws-nuke is no longer being actively maintained. We recommend users to switch to the actively maintained fork of this project at ekristen/aws-nuke.
We appreciate all the support and contributions we've received throughout the life of this project. We believe that the fork will continue to provide the functionality and support that you have come to expect from aws-nuke.
Please note that this deprecation means we will not be addressing issues, accepting pull requests, or making future releases from this repository.
Thank you for your understanding and support.