Custom collection filtering API

[johanjanssens]

Improve the filter collection state to offer out of the box support for custom collections, and implement a simple filter API developers can implement to offer advanced filtering for complex data models.

• Rename filter to query. See: https://pubs.opengroup.org/architecture/o-aa-standard/#KLP-EDA-event-command in the collection definition?
• Allow o filter on id, example: https://pages.joomlacustomfields.org/filter?filter[id][]=gt:1&filter[id][]=lt:4

Resources:

• https://levelup.gitconnected.com/elegantly-consuming-apis-using-data-transfer-objects-in-php-38ac4d8225a8
• https://github.com/funeralzone/valueobjects

Note: States should always be explicit, see: #832