implemented registerEvent with a sent value
updated monitoring UT to test registerEvent with sent value
implemented support to plugin monitoring module with self independent monitoring modules
updated documentation for new features of monitoring module
fixed small monitoring issues
small fixure doing the require of plugins on next tick
fixed small issue with register event
updated UT to test the loading of plugins and running at a preset interval of time
code review changes
UT changes after code review
code refactoring
merge topic-zabbix-system-checks