Feature 8839: Modified Installation script to install OSM with

NGUI. Default installation is with light-ui.
-n ngui will install OSM with NGUI.

Replicated the same changes as (8845) except ci_stage3.groovy

Resolved the merge conflict, fixed the indentation issue in line 586.

Change-Id: Ic89f54ea83f99df0a0189fd6e8e27be13f37a881
Signed-off-by: vijaynag <vijaynag.bs@tataelxsi.co.in>