macOS virtual files client article update for release 33.0.0

- Removed obsolete information about the different macOS builds for classic synchronization and file provider extension because we now have only one universal macOS client left.
- Clarified the conflict between the classic folder synchronization integration and file provider extension.
- Removed specific installation information because it is redundant with the general client installation documentation.
- Shifted the terminology a bit towards "file provider extension" instead of "virtual files" because the former is the official terminology used by Apple and macOS for this kind of software and what users are more likely to understand. macOS also uses this terminology in its system settings where our integration is listed.
- Clarified the benefits of enabling push notifications on the server side.
- Updated feature list.
- Updated screenshots. The user interface has changed significantly. The screenshots now have a consistent appearance. The screenshots were taken on macOS 26 Tahoe which is the latest major release as off writing. This shows that our support of macOS is up to date. Also dedicated demo content and user account was used.
- Screenshots are now in optimized JPG format instead of PNG. There is no notable quality loss but the image sizes are drastically reduced.
- Added information about the preservation of unsynchronized changes on file provider domain removal.
- Extended explanation of status symbols on file provider items.

Signed-off-by: Iva Horn <[email protected]>

Author: i2h3