Support filtering by multiple content types in Delivery API

[bjarnef]

Currently it seems Delivery API doesn't support filtering by multiple content types, which would be useful to extract content nodes in a navigation.
https://docs.umbraco.com/umbraco-cms/13.latest/reference/content-delivery-api#query-parameters-4

It would also align with how we can extract multiple properties.
Perhaps the parameter should still be contentType or support name contentTypes at some point.

Furthermore I think negation is also currently only supported for a single content type: filter=contentType:!article

A workaround is to implement a custom filter instead.
https://docs.umbraco.com/umbraco-cms/reference/content-delivery-api/extension-api-for-querying#custom-filter

https://discord-chats.umbraco.com/t/23005004/retrieving-multiple-content-types-with-the-delivery-api-newb

[bjarnef]

@kjac FYI 😁

[kjac]

I like this idea. Shouldn't be too hard to do, either 😄

Note that negation applies to the entire filter query. This means that the syntax will be:

• filter=contentType:article,news = finds documents of type article or news
• filter=contentType:!article,news = finds all other documents that those of type article and news

[kjac]

PR here: #17960

[kjac]

Will be part of 13.6 and 15.2 👍 see #17960