2.4.0

• Add Query.with_node_kinds and Query.without_node_kinds to Query. This allows lists of nodes (as returned by SiteTemplateProxy.select and other functions) to be filtered by the node kind. This is useful if you want to mix static content and documents in the same folder.
• Add SiteTemplateProxy.select_pages and Page.children to select pages (i.e. document and index nodes) only without having to manually filter the result using with_node_kinds/without_node_kinds.
• Add node_kinds to Collection.__init__ to allow constraining a collection to a specific node kind.
• Add exclude_without to Collection.__init__ and Index.__init__ to allow excluding items without a specific metadata field.
• Improve the debug output during publishing. The template publisher will now print which document is published using which template. As part of this change, Template.path was added.
• Change how Page.references is populated for top level indices. Previously, references would not be populated for a top-level index. Additionally, improve the documentation of top-level indices.
• Improve error handling when trying to sort nodes which are missing the corresponding metadata key, for example, using liara.query.Query.sorted_by_title. Previously, this would raise an exception about a failed comparison involving None, now this raises a more useful exception which contains the path to the item missing the metadata key and which key was requested.