Added Servers for Hackers

At some point, every programmer finds themselves needing to know their way around a server.

Servers for Hackers is a newsletter for those times.
Add service discovery section and Consul.

Consul is a tool for service discovery, monitoring and configuration.
Add ZooKeeper to service discover section.

ZooKeeper is a centralized service for maintaining configuration information,
naming, providing distributed synchronization, and providing group services.
Add Doozerd to service discovery section.
Update README.md
adds Bitnami to Virtualization section
Add LeoFS to Distributed Filesystems
Adding Wireshark (Troubleshooting)
Add tito to packaging
Moved "Dash" to correct topic
Added Seyren to monitoring tools.
Merge branch 'seyren' of https://github.com/jvrplmlmn/awesome-sysadmin
Merge branch 'patch-1' of https://github.com/rezen/awesome-sysadmin
Merge branch 'service_discovery' of https://github.com/bdossantos/awesome-sysadmin
Merge branch 'master' of https://github.com/walkr/awesome-sysadmin
Merge branch 'master' of https://github.com/Hunter275/awesome-sysadmin
Merge branch 'master' of https://github.com/Bitnami/awesome-sysadmin
Merge branch 'master' of https://github.com/davideschiera/awesome-sysadmin
Merge branch 'patch-1' of https://github.com/domcleal/awesome-sysadmin