The search.SiteSearch table should have params_panel_pos set to "left" and ask all Searchable models for their parameters, and handle a dynamic parameters form.

This will be used for Lino Casa. Lino Casa will have models like Appartment and House, with many parameter fields, some common, some specific.

I believe that a "source code" approach is better than a "database-stored" approach for customizing parameters. So for example if a customer wants to sell a new product with a new technology and new parameter fields, they are forced to ask a developer who will implement the new parameters. I've seen too many sites where customers had been tampering themselves in a configuration like our properties plugin, and this leads to chaotic situations and nobody wants to care for them.