Removes page/chpater addSelect global query, to load book slug, and
instead extracts base queries to be managed in new static class, while
updating specific entitiy relation loading to use our more efficient
MixedEntityListLoader where appropriate.

Related to #4823

Also moved to a non-static approach, and added a high-level class to
allow easy access to all other entity queries, for use in mixed-entity
scenarios and easier/simpler injection.

Updated query classes to align to interface for common aligned
operations.
Extracted repeated string-identifier-based finding from page/chapter
repos to shared higher-level entity queries.

Started new class for PageRevisions too as part of these changes

Also ran auto-removal of unused imports across app folder.

- Updated name to align, and differentate from new 'XQueries' clases.
- Removed old sketchy base class with app resolving workarounds, to a
  proper injection-based approach.
- Also fixed wrong translation text used in PageQueries.

Ensures fields returned match API docs and previous versions of
BookStack where we were accidentally returning more fields than
expected.
Updates tests to cover many of these.
Also updated clockwork to ignore image requests for less noisy
debugging.
Also updated chapter page query to not be loading all page data, via new
query in PageQueries.