This adds parsing of page content so that headers apply a boost to
scores in the search term index.
Additionally, this merges title and content terms to reduce the amount
of stored terms a little.
Includes testing to cover.
On restore, added a link to the parent deletion restore if any exists
on a cascading parent. Added a test to cover this case to ensure its shown.
Also tweaked default empty state message on recycle bin item list to align
with new column count.
Also done a little existing code cleanup including a getUrl helper on
the deletion items.
Related to #2682 & #2594
Phasing out the view service from being a generic 'service' class,
moving the core create/delete methods into the model.
The idea is that the existing query work will need to interlink
with the favourite system so maybe we have a (or many composable)
query building classes rather than mixing query building and
create/delete work as per the old service.
Removed some common functions from other entities.
Aligned implementation of getUrl()
Cleaned phpdocs and added typehinting.
Also extracted sibling search logic out of controller.
Tools seems to fit better since the classes were a bit of a mixed bunch
and did not always manage.
Also simplified the structure of the SlugGenerator class.
Also focused EntityContext on shelves and simplified to use session
helper.
