Update filters to conform to Logstash 5.4

[gabelilly]

I wasn't able to test all of the filters properly, but I'm pretty sure they should be working. It at least got me up and running with the logs I was parsing. Hopefully others can test it more thoroughly. Thanks.

Relates to Issue #37

[bgedney]

So, I can parse without getting ruby exceptions, so that's an amazing, but I am getting grok parse failures. I'm also not getting any Raw data into the associated fields (but the fields themselves are getting created according to Kibana).

Also, had division errors from 2082, but I think that's just because there is nothing to process at this point.

Edit: I'm an idiot and forgot to configure the multi-line codec. It works great. I suggest merging this pr.

[bitsofinfo]

Would like to request some other prior contributors to test this PR against their setups if they can, the more eyes the better thanks

@breml
@MWilkinson
@saknopper

[saknopper]

I don't have an active setup at the moment. Though I might have some time to play around with logstash 5.4 in the following weeks. No promises though...

[breml]

I no longer work for the company, where we used this logstash configuration. Therefore I have no opportunity to test with recent Logstash versions. Maybe @usp-rol or @elmux may help.

[usp-rol]

There is little chance to test against logstash5 since we still are running on logstash2. I fear migration to logstash5 (for this component) will not take place within the next time and thus testing against logstash5 won't be planned soon...

still I will ask and come back if there would be good news.

[gabelilly]

@bitsofinfo What's your recommendation on this? Seems like most people that can test it have and it works for them. How would you like to move forward? Thanks.