ApiWrapper: support image upload and download by user type and subject

[tylerthome]

Overview

To enable hosts to share photos of their home and of themselves, add methods to the ApiWrapper supporting listing images and file transfer

Action Items

Add the following client-side API methods:

• [x] POST /api/host/images/{subject}, where request body has the shape {email: string}
• [x] POST /api/uploadImage, wrapper should accept a File, an email and subject as input, request body should be an instance of FormData including email and and the file
• [x] GET /api/host/images/download/{fileId} where response body is Blob

Resources/Instructions

See following comments

[tylerthome]

Resolved by PR #251