Add APIs to register in gmainloop through context

:Release Notes:
Add APIs to register in gmainloop through context

:Detailed Notes:
New APIs are LSGmainContextAttach and LSGmainContextAttachPalmService

:Testing Performed:
Openwebos image for emulator was built and checked

:QA Notes:

:Issues Addressed:
[GF-14219] Add LCSGmainontextAttach(LSHandle *, GMainContext *, LSError *) call

Open-webOS-DCO-1.0-Signed-off-by: Alekseyev Oleksandr<alekseyev.oleksandr@lge.com>

Change-Id: I66b374d5e36afe6be66afc53796dbef7d333010f
Reviewed-on: https://g2g.palm.com/3215
Reviewed-by: Build Verification
Reviewed-by: Alekseyev Oleksandr <alekseyev.oleksandr@lge.com>
Tested-by: Alekseyev Oleksandr <alekseyev.oleksandr@lge.com>
Reviewed-by: Anatolii Sakhnik <anatolii.sakhnik@lge.com>