Improve Auto Upload UI/UX and Add Advanced Customization Options for Upload Paths

**Is your feature request related to a problem? Please describe.**
Yes. The current automatic upload feature in the Nextcloud Android app has several issues that affect both usability and convenience.

1. **UI/UX Problems:**
- The upload interface becomes very laggy when uploading a large number of files.
- There is no visible, detailed progress indicator for uploads — such as “Uploaded 20MB / 100MB” or a clear progress bar with percentage.
- Background upload notifications are too minimal and lack meaningful status updates.
- These UI limitations make it hard for users to track upload progress.
> Suggestion: Refer to Synology’s *Photos* app for a more responsive and informative automatic upload experience.

2. **Convenience & Customization Issues:**
- Currently, upload rules can be set per folder, which is great — but there are no options to:
- Copy the rule settings (like path and conditions) from one folder to another.
- Set a default path structure for uploads.
- For example, I want to automatically upload DCIM photos to `/nextcloud/phone-1/DCIM/` or organize them like `/nextcloud/[custom-folder]/DCIM/`.
- This level of customization is especially useful when managing uploads from multiple folders or devices.

**Describe the solution you'd like**
- Add detailed and smooth upload progress feedback (progress bar, MB uploaded, percentage, etc.).
- Improve the background notification with real-time status and remaining size.
- Support one-click copying of upload rules between folders.
- Allow users to define default upload paths for each folder or set a global default upload directory.

**Describe alternatives you've considered**
Manually configuring every folder or organizing uploads outside the app, which is inefficient and error-prone.

**Additional context**
Thank you for the great work on this app. Improving the automatic upload functionality will greatly benefit users who rely on Nextcloud for complete photo/video backup.