[IMPROVEMENT] Permanent custom bundles (bundles as app groups)

### Please confirm these before moving forward.

- [x] I have searched for my feature proposal and have not found a work-in-progress/duplicate/resolved/discarded issue.
- [x] This improvement refers to an existing feature. If you want to suggest a new feature, please use [this template](https://github.com/marticliment/WingetUI/issues/new?assignees=marticliment&labels=new-feature&projects=&template=feature-request.yml&title=%5BFEATURE+REQUEST%5D+%28Enter+your+description+here%29).
- [x] This improvement is not a bug. If you want to report a bug, please use [this template](https://github.com/marticliment/WingetUI/issues/new?assignees=marticliment&labels=bug&projects=&template=bug-issue.yml&title=%5BBUG%5D+%28Enter+your+description+here%29).

### Describe the improvement

Currently bundles can serve as a temporary export/import option: you add a few packages to a bundle, export it, then creating a new bundle will delete the old one.
Instead it would be better if you could have permanent bundles that serve as collection/group of apps, for example, you could group "Utilities", "Music", "Graphics". Or maybe "essential", "test new", etc.

### Describe how this improvement could help users

It would help sharing installed apps across different users/devices