sphinx: removing aggregation freamework domain, and adding objects to the mongodb domain

Conflicts:
	source/applications/aggregation.txt
	source/includes/fact-agg-sort-limit.rst
	source/reference/aggregation.txt
	source/reference/aggregation/concat.txt
	source/reference/aggregation/geoNear.txt
	source/reference/aggregation/match.txt
	source/reference/aggregation/millisecond.txt
	source/release-notes/2.4.txt