Implement alert storm protection for all media types

It will be nice to have builtin functionality to protect Zabbix environment from alert storm.

For example many of external Emails services like Offiice365 and other have build in over flood protection and in case of alert storm can block all messages from Zabbix.

So, it will be nice to have some kind of "not more then ___ messages in ___ seconds" parameter in Media types.