Alarm: Bind start-of-week to the locale

Instead of relying on a manual setting that's only initialized once
with the bootstrap/post-setupwizard locale, dynamically bind the
days-of-week order to the active locale, in real time.

Change-Id: Ied25a867241a3269a7e69e16c3038c87cf5d2aa9
JIRA: CYNGNOS-1822
(cherry picked from commit ae8bcce1)