FR-32: Property images

Description

As an authenticated user, I want to upload images of my property when creating an advertisement so others can picture the property better.

Context

Useful links:

• https://hexdocs.pm/phoenix/1.7.10/file_uploads.html

Acceptance Criteria

• AC1 - An authenticated user should be able to upload images when creating an advertisement.
• AC2 - Image count should be between 1 and 5 (both inclusive).
• AC3 - The images should be uploaded to the application disk space.
• AC4 - All images should be visible in the detailed advertisement view.
• AC5 - First uploaded image should be shown in the full list (homepage) view as a smaller image.