LPS-39662 Introduce the AssetPublisherUtil.processQuery() method as a first step to allow for better extensibility of dynamic queries
LPS-39662 Introduce the AssetQueryProcessor interface and extract the existing logic to filter by custom user attributes as the first implementation.
LPS-39662 Make the form to setup the asset query configurable

Move the custom user attributes part of the form as an extended form section since some people may not want it. I've left the other configuration panels as they were (at least for now).
LPS-39662 Allow to register asset query processors from the plugins
LPS-39662 added log messages
LPS-39662 Make property mergeable and extendable
LPS-39662 Use the new API
LPS-39662 Change class and method names to reflect handled type
LPS-39662 Change property name to reflect which form is configuring
LPS-39662 Add @Override
LPS-39662 Use full name
LPS-39662 Use longer var name, keep it consistent with addSelection in the same class
LPS-39662 Rename
LPS-39662 Sort, no logic changes
LPS-39662 SF
LPS-39662 Missing parts needed by Liferay IDE
LPS-39662 Consistency
LPS-39662 Is this statement true? What does this have to do with document library?