Document Image API

[project0]

Issue Summary

Apparently a image API exist for uploading/deleting and listing images exists. (What can be used in templates).
It is crucial for managing templates in automated way that we can also manage assets via API.

Examples

POST https://api.sendgrid.com/v3/images (upload content, response in json)
GET https://api.sendgrid.com/v3/images?page_size=50 (list)
DELETE https://api.sendgrid.com/v3/images/<id>