aws-sdk-go-v2 multipart upload poc

There are 2 examples of uploading multipart with aws-sdk-go-v2:

1. Manually, starting by calling s3Client.CreateMultipartUpload
2. S3 Manager, a feature implemented by S3

1. git clone the repo

2. populate your AWS credentials in ~/.aws/config

3. chdir into either the manual_multipart or manager directories

4. find a file that you would like to upload and update the const variables at the top

5. within the example directory, run:

    go run .
   

6. look in the s3 bucket and find the uploaded file