Allow registering activities which has "method" started with "luna://"

:Release Notes:
Allow registering activities which has "method" started with "luna://".

:Detailed Notes:
Change URL validator to allow "luna://" as well as "palm://". Allow
registering activities which has "method" started with "luna://".

:Testing Performed:
Tested according to the ticket description using starfish image.

:QA Notes:

:Issues Addressed:
[GF-11716] Can't register activity that has "callback" which has
"method" started with "luna://" in Activity Manager

Open-webOS-DCO-1.0-Signed-off-by: Oleg Yablokov <oyablokov@luxoft.com>

Change-Id: I4c2eee269b21ddeeeeace9c228bd979cf0dd3f75
Reviewed-on: https://g2g.palm.com/3018
Reviewed-by: Build Verification
Reviewed-by: Oleg Yablokov <oyablokov@luxoft.com>
Tested-by: Oleg Yablokov <oyablokov@luxoft.com>
Reviewed-by: Mark Bessey <mark.bessey@lge.com>
Reviewed-by: Jason Lai <jason.lai@lge.com>
Reviewed-by: Alan Levi <alan.levi@lge.com>