doc: Explain what a `query resource` is

Fixes #693

(cherry picked from commit 870ebc18aa020402e79ba27f6b104e616e544189)

Conflicts:
	doc/manuals/datamodel/search.rst
doc: Explain all default fields in a resource

(cherry picked from commit 2b68ecb2f41c3813a9f448045b8ad457c4225650)