webos_enhanced_submissions: Add limited support for multiple repositories

:Release Notes:
Until now we were able to support multiple repositories in SRC_URI as
long as only one of them had 'tag' parameter, now when we weren't
setting this param, we need another way to mark which repository gets
the SRCREV from this bbclass, use 'name' parameter with special value
'main'.

:Detailed Notes:

:Testing Performed:
Only build tested.

:QA Notes:
No change to image.

:Issues Addressed:
[ES-791] Enable webos_enhanced_submissions sanity checks
[BHV-6871] CCC: Enable webos_enhanced_submissions sanity checks

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: Idb54566e81ecac051e589e2f26dd548ea85b549d
Reviewed-on: https://g2g.palm.com/5444
Reviewed-by: DCO Verification
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Tested-by: Martin Jansa <Martin.Jansa@lge.com>
Build: Susan Montooth <susan.montooth@lge.com>
Reviewed-by: Susan Montooth <susan.montooth@lge.com>