Add keepalive to logstash source

[dnegreira]

Issue

112

Solution

Add a keepalive to the logstash source so that if it doesn't receive a packet for one hour, it will drop the connection and free the resources.

Testing Instructions

Mostly the same instructions as described on #112 - Just verify that the connections are dropped.

Release Notes

[simskij]

@dnegreira can you please rebase your pr with pgp-signed commits, so i'll be able to merge it? thanks :)

[dnegreira]

@simskij should be good to go now :)