Added NS subscription to html_out

Added Ns subscription url to html_out.
Since in html there was no explict link for favicon.ico, browser by
default makes GET request to /favicon.ico NBI reponse was 404.
Added OSM favicon.ico and gave explicit link to static folder.

Change-Id: Id0088ca09bfc5000e487ab44ac678fab49919c37
Signed-off-by: K Sai Kiran <saikiran.k@tataelxsi.co.in>