[Bug]: `hide_media` and `show_images` user settings need to be split out.

### Requirements - [x] Is this a bug report? For questions or discussions use https://lemmy.ml/c/lemmy_support or the [matrix chat](https://matrix.to/#/#lemmy:matrix.org). - [x] Did you check to see if this issue already exists? - [x] Is this only a single bug? Do not put multiple bugs in one issue. - [x] Do you agree to follow the rules in our [Code of Conduct](https://join-lemmy.org/docs/code_of_conduct.html)? - [x] Is this a backend issue? Use the [lemmy-ui](https://github.com/LemmyNet/lemmy-ui) repo for UI / frontend issues. ### Summary In working on https://github.com/LemmyNet/lemmy-ui/issues/4211 , I found that the UI can do two things related to post media, but is incorrectly combining them. 1. Hide media in the UI (meaning the posts are still shown) - Useful for ppl with sensory overload and want to see less images on their front page. 2. Hide meme posts (A special post fetch that hides meme content / image and video posts). - Useful for ppl who don't want to fetch any meme content. These are both useful, but the settings need to be split out. We already have 2, called `hide_media`. I'm probably going to rename it to `hide_memes` (even tho it also hides video posts. Can't think of a better name tho.) The other I'm going to create `show_media`, which exists alongside the other front end settings like `show_avatar`, `show_animated_images`. ### Steps to Reproduce See above. ### Technical Details See above. ### Version mai ### Lemmy Instance URL _No response_