drop the jruby-jms dependency (to avoid Ruby warnings)

[kares]

jruby-jms repo has been archived by the owner, which means we can not submit patches or report issues upstream (technically issues can be submitted but won't get fixed).

there's Fixnum/Bignum warnings at the library level that are annoying and should be dealt with: https://github.com/reidmorrison/jruby-jms/compare/master...kares:patch-1

there's a few options forward:

• vendor the jruby-jms gem, in the plugin, and drop the dependency
• fork the gem under a new name and start using that as a dependency
• drop the dependency completely and use the Java API directly

first option might be the easiest to take for the foreseeable future ...

[jsvd]

I'm tempted to go for option 1 (vendoring) with a caveat: we should merge the JMS input and output into the logstash-integration-jms. This way we don't have to vendor the code into two repositories and duplicate any work we do to this library.