feat: CustomJsonLd for carousel

[mkaynakk]

Description of Change(s):

Hi,

Optional properties can be added and the type of items can be customized in carousel.

Why was it needed?

• An item's type is 'VideoGame, MusicRecording' etc. can be a value. So the type can be set.
• Position information can continue instead of being reset when the page changes.

Related Document
https://schema.org/ItemList (Example 3)

Test

• Have you updated the documentation to go with your changes? Yes
• Have you written or updated unit tests? Yes

All tests are passing.

Thanks for your work :)

[mkaynakk]

any news? @garmeeh

[jwilson114]

Very much needed.

[garmeeh]

Hey @mkaynakk sorry about the delay.

What is the use case for this?

Wondering should we add url also to the item?

[mkaynakk]

It can be used on pages in a numerical incremental pagination structure. A url information can be passed at the beginning of the page, and I think this will be sufficient. @garmeeh

[kjprince]

Can we merge this change? Would be great to use this for blog category pages as shown here:
https://webmasters.stackexchange.com/questions/119808/schema-org-structured-data-for-blog-category-page