consolidated main cronjob server on virtual machine together with build_log database;
eliminated special tricks for Gentoo;
import plain_identify logs, export all logs for backup;
run build_release, build_history_base in parallel to remote_build_history tasks;

--HG--
rename : Admin/cronjob/crontab.lxbroy10 => Admin/cronjob/crontab.server

clarified README;

plain identify job for Isabelle + AFP, independent of any Isabelle technology;

basic setup for Isabelle cronjob;