[Feature Request]: Batch selection with actions

### Guidelines

- [X] I have searched the [issue tracker](https://github.com/FreeTubeApp/FreeTube/issues) for a feature request that matches the one 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.

### Problem Description

Hi I would like to request a feature to

- select all/select specific videos on subscriptions page with ability to:
- batch copy links
- batch download videos
- batch mark as watched/unwatched

The reason I'm requesting this is because I've been watching videos on my iPhone on uYou, and I wanted to be able to mark all the videos I watched with ease, because right now it's a little bit of a pain. I also have been wanting to download certain videos in a playlist and going into each video and downloading is also very tedious.

### Proposed Solution

I would like the ability to select each individual video by Alt clicking, being able to batch select to a point by Shift clicking, or be able to select all videos by pressing "Cltr+A". Then when videos are selected, I would like to be able to batch copy video links, batch download videos, or batch mark video watched/unwatched. I would like this to be an option on the subscriptions page to bring the option to manage videos in your subscriptions.

### Alternatives Considered

Another solution would be able to add download option to the triple dots without entering video, mark all videos watched/unwatched in an entire specific channel.

### Issue Labels

ease of use improvement, improvement to existing feature, new feature, new keyboard shortcut

### Additional Information

_No response_