[Feature Request]: Low data mode / data saving mode

### Guidelines

- [X] I have searched the issue tracker for [open](https://github.com/FreeTubeApp/FreeTube/issues?q=is%3Aopen+is%3Aissue) and [closed](https://github.com/FreeTubeApp/FreeTube/issues?q=is%3Aissue+is%3Aclosed) issues that are similar to the feature request I want to file, without success.
- [X] I have searched the [documentation](https://docs.freetubeapp.io/) for information that matches the description of the feature request I want to file, without success.
- [X] This issue contains only one feature request.

### Problem Description

Low data mode is a feature on OSes like iOS and MacOS that reduces data use whenever possible. [Data saving mode](https://www.youtube.com/watch?v=aimjiZXyTFU) is a feature that has been tested for the YT Mobile app, although it appears to have been replaced by "Video quality preferences" -> "Video quality on mobile networks" / "... on wifi" -> "Data saver" (lower picture quality). The main benefit of these features is allowing users to conveniently lower data usage in one quick motion when they need to do so. Common use cases are traveling, living in an area with inconsistent internet access, etc.

### Proposed Solution

A General Setting called `Low Data Mode` or `Data Saving Mode` that alters and freezes (i.e., sets to `disabled`) certain settings while it is enabled. These settings selections would be optimized for reducing data usage and API calls. When the mode is disabled, the pre-existing values of these settings are restored to their previous values.

This can be refined more, but here are some ideas:
- Default Quality setting's range limited to 480p
- Consider using lower resolution video thumbnails
- Use lower resolution images in community posts, currently we always pick the largest one (1000px+ in most cases).
- Disable "Auto Load Next Page" if the user enabled it (it is disabled by default but seems like a good candidate to make sure it is disabled if low data mode is enabled).
- Disable "Check for Latest Blog Posts" (we haven't done a blog post in a long time, so the users aren't missing out on anything and it's one less request).
- lower audio quality
- default Recommended Videos / Playlist autoplay disabled
- RSS disabled (if not too many subscriptions)
- Fetch Feed Automatically disabled

### Alternatives Considered

Two important aspects of this feature are its convenience (one-click at any time, not just on profile creation) and its reversability (it temporarily applies certain settings but re-applies the previous values when the mode is disabled).

This can partially be achieved by a user creating a settings template that has these specific settings (see https://github.com/FreeTubeApp/FreeTube/issues/1996#issuecomment-2105935459). Expecting every user with that use case to create this template themselves might be too onerous, though, so that might have to be done with #612 as well for this need to be totally fulfilled. If nothing else, this story exists as a further explication of what one of those preconfigured settings profiles could be.

### Issue Labels

new feature, new optional setting

### Additional Information

Edited on 1/8/24 to accommodate commenter suggestions.
Note: May need to come with or be following a UX improvement to showing why a setting is disabled on hover/focus, as this will disable a good number of them.