Add Dynamic MIME Types to S3 Upload Function

Current Behavior

We currently hard code the MIME type in the upload to S3 function.

Purpose

We upload various file types and we should properly set their MIME types.

Plan

This code has been written for the plugins pipeline and should be mostly ready to go.

Acceptance Criteria

Code review of dynamically adding the MIME type (content-type and content-encoding) for each document uploaded by the pipeline to S3.