Default to standard retry

[mullermp]

Sets the default retry strategy to standard.

This is a mild breaking change, rendering some config values useless (since standard doesn't have too many configurable options).

DynamoDB extended retries will include a new default of 10 retries but no configurable jitter/backoff policy unless configured back to legacy.

Other changes to the retry plugin are rubocop related.

[github-actions[bot]]

Detected 1 possible performance regressions:

• aws-sdk-dynamodb.gem_size_kb - z-score regression: 223.0 -> 223.5. Z-score: Infinity