distros.conf: switch testing back to jessie for starting with 0.62

Signed-off-by: Andreas Beckmann <anbe@debian.org>
piuparts.conf.pejacevic: add new suite: jessie2proposed.
piuparts.conf.piu-slave-1und1-01: merge changes from pejacevic config but replace amd64 with i386.
crontab-master.in: update webpages every six hours.