[CARBONDATA-1702] [Segment-Reading] added doc for query from specified segments feature
[CARBONDATA-1702] [Segment-Reading] added doc for query from specified segments feature

add doc for query from specified segments

This closes #1727

sgururajshetty/carbondata,manishgupta88/carbondata,manishgupta88/incubator-carbondata,sgururajshetty/carbondata,sgururajshetty/carbondata,jackylk/incubator-carbondata,ravipesala/incubator-carbondata,jatin9896/incubator-carbondata,zzcclp/carbondata,jatin9896/incubator-carbondata,manishgupta88/carbondata,ravipesala/incubator-carbondata,zzcclp/carbondata,manishgupta88/incubator-carbondata,zzcclp/carbondata,manishgupta88/carbondata,manishgupta88/carbondata,ravipesala/incubator-carbondata,ravipesala/incubator-carbondata,manishgupta88/incubator-carbondata,zzcclp/carbondata,jackylk/incubator-carbondata,jackylk/incubator-carbondata,jatin9896/incubator-carbondata,jackylk/incubator-carbondata,manishgupta88/incubator-carbondata,zzcclp/carbondata