remove elastiflow (project archived)

- ref. https://github.com/awesome-foss/awesome-sysadmin/issues/405

README.md

@@ -507,7 +507,6 @@ _See also: [IT Asset Management]([Ralph](#it-asset-management))_
 - [cadvisor](https://github.com/google/cadvisor) - Analyzes resource usage and performance characteristics of running containers ([Source Code](https://github.com/google/cadvisor)) `Apache-2.0` `Go`
 - [checkmk](https://checkmk.com/) - Comprehensive solution for monitoring of applications, servers, and networks. ([Source Code](https://github.com/tribe29/checkmk)) `Python/PHP`
 - [EdMon](https://github.com/Edraens/EdMon) - A command-line monitoring application helping you to check that your hosts and services are available, with notifications support. `MIT` `Java`
-- [ElastiFlow](https://github.com/robcowart/elastiflow) - Network flow Monitoring (Netflow, sFlow and IPFIX) with the Elastic Stack.
 - [eZ Server Monitor](http://www.ezservermonitor.com) - A lightweight and simple dashboard monitor for Linux, available in Web and Bash application.
 - [Flapjack](http://flapjack.io/) - Monitoring notification routing & event processing system.
 - [Healthchecks](https://healthchecks.io/) - Monitoring for cron jobs, background services and scheduled tasks.