[Feature Request]: Dedicated Sidebar Button to Exit App

### 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

The way I am using Freetube it is undesirable to close via the top bar cross or Alt-F4.

### Proposed Solution

Would be really useful to have an exit application option on the sidebar

### Alternatives Considered

None

### Issue Labels

ease of use improvement

### Additional Information

_No response_