Filters visible layers for packaging offline project

[SeqLaz]

trafficstars

This PR integrates enhancements to the functionality mentioned in issue #438

https://github.com/user-attachments/assets/70072970-a7e6-4f8e-93ec-c0e9f5117a9f

[suricactus]

@SeqLaz thanks for your amazing contribution!

I left a few comments, mostly nit-picks. One major questions is if we can move the filter to the top of the table, between "Layers" label and the table itself. I think it makes more sense as in QGIS most of the UI is from top to bottom. Also the eye icon on the top-right can be moved on the same row as the other three filters.

[SeqLaz]

Hey @suricactus I did the suggested changes!

https://github.com/user-attachments/assets/b30b623d-1358-4806-bf7d-6d30ee1a09a8

[SeqLaz]

New Design

[suricactus]

Thanks a lot of the amazing contribution!