Add 5.0.2 and 5.1.0 online repository build job description files

Added 5.0.2 and 5.1.0 repository description files to be able to
build repositories with release_build_handler script.

Change-Id: I0ced13822435023b23842f923a94a390c8ec6749
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Reviewed-by: Matti Paaso <matti.paaso@digia.com>
Reviewed-by: Iikka Eklund <iikka.eklund@digia.com>
Improve release_build_handler.py

Add functionality to handle online repository updates for production
server. Minor refactoring.

Change-Id: I62b38612298668e914dc7adff63787e1f24bd645
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Reviewed-by: Matti Paaso <matti.paaso@digia.com>
Reviewed-by: Iikka Eklund <iikka.eklund@digia.com>