Add custom properties on CAYW endpoint

[palukku]

Currently, the CAYW endpoint only inserts the citation key. The goal is to also include the custom properties shown in the UI when selecting an entry (see screenshots).

• Add a custom popup in SelectedItemsContainer.java.

• Consider creating a dedicated popup class that receives the CAYWEntry.

• Maybe use some kind of enum or something like that to handle abbreviations like in Zotero which is shown here in the table with the fields so we could change those later more easily.

• Extend the CAYWEntry class to hold the additional custom properties so they are accessible later in the formatters.

• Update the formatters to support the new properties, extend citation style handling to include them.

Obligatory:
Know how the different formats handle the specific properties, you can see a list with links to most of the corresponding documentations here.

[subhramit]

Good third/fourth issue?

[palukku]

I would say fourth