Improve notifications in upload and createlinks

An error notification should be shown when one of the uploads has failed. The overlay should also not disappear so the user can see which file has not gone through successfully.

Also, the notification should be updated to have one for:

- Single file successful - My library only: 
```
The file "<File name> (link)" has been added to My Library (link).
```
- Single file successful - My library + Group library: 
```
The file "<File name> (link)" has been added to My Library (link). and <Group> Library (link).
```
- Multiple files successful - My library only:
```
<x> files have been added to My Library (link).
```
- Multiple files successful - My library + Group library: 
``
`<x> files been added to My Library (link). and <Group> Library (link).
```