User Guide update - Query Builder (fixes #2512)

1) Changed the grouping for better readability, in the query builder writeup
2) Added return value descriptors for all methods
3) Added default setting to query builder configuration writeup.

The TOC sidebar is much better than before, though still a bit messy. This will need fixing with the sphinx theme update, being done separately.

Signed-off-by:James L Parry <jim_parry@bcit.ca>
Merge pull request #3373 from jim-parry/userguide/querybuilder

User Guide update - Query Builder (fixes #2512)