Improve search configuration parameters mapping

In Designer

• tabs
• main menu pages listing

The params field is always visible (i.e. not in the advanced options)

• In left menu items search

The params field is still in advanced options (we don't need it because we have a search form)

For all screens above

• When the provider field is not set, the params field is disabled and a contextual information icon is available. Clicking on it displays a dialog saying

  Select provider to map query parameters

• When a provider is selected, the predicates of the page provider are shown as read-only. A field next to each is available for the user to do the mapping
• The mapping field provides autocomplete (this part can be put in a separate ticket if necessary)
• Designer generates the corresponding JSON configuration for the mapping. When no mapping is done, Designer does not generate a value for that parameter (i.e. we don't generate a blank / null value, we just ignore it).

For existing projects, mapping needs to be retroactive (i.e. we have to be able to read the existing one and map it back inside the UI).