Docs: fix typo

Closes #8111
Fixing aggregation call to facets

This is already fixed in master thanks to the removal of facets.
Docs: Typo: s/by/be/

Closes #8114
Improve amibiguous ES_HEAP_SIZE warning in deb init script

Closes #3554
Add debug logging to help diagnose intermittent upgrade test failures.

Also fixed indentation in ElasticsearchMergePolicy.
Remove unnecessary log level setting in upgrade test.
Merge pull request #8121 from pickypg/fix/searchrequestbuilder-aggregation-not-facet

Fixing SearchRequestBuilder aggregations call to facets
Fixing copy/paste mistake in SearchRequest.extraSource's exception message.