Patient/Doctor records upload

[ARMmaster17]

Summary

From the original project specification, and further input from the "customer", both the patient and the doctor users need the ability to upload files to the records pages.

Blocks #136
Blocked by #26 and #57

Implementation

• Implement POST route and set as target of HTML form on records page.
• Create a FileEntity and upload to storage provider.
• Populate records page with list of all FileEntity instances in the DB (don't worry about filtering by who uploaded what. ACL support will be a separate ticket).