HPCC-10834 DOCS:Stand. use of Thor,Roxie

HPCC-10834 DOCS:Stnd use of Thor,Roxie
Standardize usage of Thor, Roxie, and hThor in the docs.

@JamesDeFabia please review

Signed-off-by: g-pan <greg.panagiotatos@lexisnexis.com>