Transfer Manager Durability and Part Size Updates

[GarrettBeatty]

This change cherry picks commits related to s3 transfer manager durability that we want to release. All of the commits (except for number 2) have been approved already.

Description

1. Increase multipart upload default part size to 8MB (https://github.com/aws/aws-sdk-net/pull/4032[)](https://github.com/aws/aws-sdk-net/pull/4096/commits/cf2b846acc012daccf58f515e6b7f7ca632f23ba)
2. 7c56fce <----- manual commit which is a subset of hhttps://github.com/Added PutObjectResponse to TransferUtilityUploadResponse mapping #4045 and just includes the changes related to updating generator to give s3 unit test project access to the s3 project. I basically just did a cherry pick of this PR and then did git reset HEAD~ and then re-added only the files i needed from this PR.
3. Add missing fields to Transfer Utility request objects (https://github.com/aws/aws-sdk-net/pull/4056[)](https://github.com/aws/aws-sdk-net/pull/4096/commits/a3dcb313f20c3c3c62cc3b28d3a3267098632160)
4. Fix issue with HeadersCollection in ResponseMapperTests
5. Add additional validation to UploadPartRequests in Transfer Utility (https://github.com/aws/aws-sdk-net/pull/4083[)](https://github.com/aws/aws-sdk-net/pull/4096/commits/e6f904f8af08af415417f375c4b94312701c698f)
6. create tuabortmultipartuploadrequest (https://github.com/aws/aws-sdk-net/pull/4093[)](https://github.com/aws/aws-sdk-net/pull/4096/commits/9b3066d1336dff46b2a964fca0f303556943f740)

Motivation and Context

Testing

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project
• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have read the README document
• I have added tests to cover my changes
• All new and existing tests passed

License

• I confirm that this pull request can be released under the Apache 2 license