feat(feed/posts): update post feed to handle media rendering, including sorting, linking messages, downloading attachments, and optimized media placeholders and aspect ratios

[domw30]

What does this do?

• This update enhances the post feed by implementing media rendering, including sorting, linking messages with their media files, handling media download, and optimizing media display with placeholders and aspect ratio adjustments.

Why are we making this change?

• We are making this change to improve the user experience by ensuring that media in posts is rendered properly, displayed with appropriate dimensions, and can be downloaded, enhancing the functionality and usability of the post feed.

How do I test this?

• run tests as usual
• run UI > create/open social channel and send images

Key decisions and Risk Assessment:

Things to consider:

1. How will this affect security?
2. How will this affect performance?
3. Does this change any APIs?