improving configuration loading

* logging more information (since loggers are enabled earlier)
* params can now be defined either as "(param(key foo)(value bar))" or
  as "(param foo bar)"
* param loading code is shared among all classes supporting "(param)"
  subnodes
adding setenv and unsetenv (with local and ssh support)
web console shows setenv and unsetenv config
web console: more links between pages
every batch receives env variables TASKID, FQTN, TASKGROUPID, TASKREQUESTID