Feature request: Linkwarden sync to root collection folder

### Describe the feature you'd like to request

Currently, Floccus only allows syncing to a Collection created in Linkwarden. This then shows as nested collections which are bit harder to navigate if you have multiple folders in browser.


### Describe the solution you'd like

To make it easier, Instead of syncing to existing collection, Floccus could be setup to sync to the root of the collection as `/` which is the Unorganized collection.
This would make it so that the user does not have to create a collection where the sync would go through


The result would look like this:

### Describe alternatives you've considered

I'm aware that I can create 2 profiles for each folder/collection however with the option described above, you'd only need one profile to do all the synchronization