Remove broken plugins from documentation

I generated a plugins status with `rake generate_plugins_versions` on the master branch.

There are many plugins which will not install at all in Logstash. Generated this list with the following:

```
% rake generate_plugins_versions

% cat plugins_version_docs.json | jq '.failures | to_entries[] | .key' | fex '"1' | sed -e 's@^.*$@* [&](https://github.com/logstash-plugins/&)@'
```

# MASTER

Plugins which fail to install in master

* [logstash-filter-punct](https://github.com/logstash-plugins/logstash-filter-punct)
* [logstash-codec-compress_spooler](https://github.com/logstash-plugins/logstash-codec-compress_spooler)
* [logstash-codec-oldlogstashjson](https://github.com/logstash-plugins/logstash-codec-oldlogstashjson)
* [logstash-filter-cipher](https://github.com/logstash-plugins/logstash-filter-cipher)
* [logstash-filter-collate](https://github.com/logstash-plugins/logstash-filter-collate)
* [logstash-input-gemfire](https://github.com/logstash-plugins/logstash-input-gemfire)
* [logstash-input-zenoss](https://github.com/logstash-plugins/logstash-input-zenoss)
* [logstash-input-zeromq](https://github.com/logstash-plugins/logstash-input-zeromq)
* [logstash-output-zeromq](https://github.com/logstash-plugins/logstash-output-zeromq)
* [logstash-output-gemfire](https://github.com/logstash-plugins/logstash-output-gemfire)
* [logstash-filter-metaevent](https://github.com/logstash-plugins/logstash-filter-metaevent)
* [logstash-filter-zeromq](https://github.com/logstash-plugins/logstash-filter-zeromq)
* [logstash-codec-s3plain](https://github.com/logstash-plugins/logstash-codec-s3plain)
* [logstash-filter-oui](https://github.com/logstash-plugins/logstash-filter-oui)
* [logstash-input-fluentd](https://github.com/logstash-plugins/logstash-input-fluentd)
* [logstash-filter-unique](https://github.com/logstash-plugins/logstash-filter-unique)
* [logstash-output-elasticsearch_java](https://github.com/logstash-plugins/logstash-output-elasticsearch_java)
* [logstash-codec-csv](https://github.com/logstash-plugins/logstash-codec-csv)
* [logstash-output-rados](https://github.com/logstash-plugins/logstash-output-rados)
* [logstash-filter-lookup](https://github.com/logstash-plugins/logstash-filter-lookup)
* [logstash-output-zookeeper](https://github.com/logstash-plugins/logstash-output-zookeeper)
* [logstash-output-monasca_log_api](https://github.com/logstash-plugins/logstash-output-monasca_log_api)
* [logstash-filter-cloudfoundry](https://github.com/logstash-plugins/logstash-filter-cloudfoundry)

# 5.6 failures

% cat plugins_version_docs.json | jq '.failures | to_entries[] | .key' | fex '"1' | sed -e 's@^.*$@* [&](https://github.com/logstash-plugins/&)@' | sort
* [logstash-codec-csv](https://github.com/logstash-plugins/logstash-codec-csv)
* [logstash-codec-oldlogstashjson](https://github.com/logstash-plugins/logstash-codec-oldlogstashjson)
* [logstash-codec-s3plain](https://github.com/logstash-plugins/logstash-codec-s3plain)
* [logstash-filter-cipher](https://github.com/logstash-plugins/logstash-filter-cipher)
* [logstash-filter-cloudfoundry](https://github.com/logstash-plugins/logstash-filter-cloudfoundry)
* [logstash-filter-collate](https://github.com/logstash-plugins/logstash-filter-collate)
* [logstash-filter-lookup](https://github.com/logstash-plugins/logstash-filter-lookup)
* [logstash-filter-metaevent](https://github.com/logstash-plugins/logstash-filter-metaevent)
* [logstash-filter-punct](https://github.com/logstash-plugins/logstash-filter-punct)
* [logstash-filter-unique](https://github.com/logstash-plugins/logstash-filter-unique)
* [logstash-filter-zeromq](https://github.com/logstash-plugins/logstash-filter-zeromq)
* [logstash-input-fluentd](https://github.com/logstash-plugins/logstash-input-fluentd)
* [logstash-input-gemfire](https://github.com/logstash-plugins/logstash-input-gemfire)
* [logstash-input-zenoss](https://github.com/logstash-plugins/logstash-input-zenoss)
* [logstash-input-zeromq](https://github.com/logstash-plugins/logstash-input-zeromq)
* [logstash-output-elasticsearch_java](https://github.com/logstash-plugins/logstash-output-elasticsearch_java)
* [logstash-output-gemfire](https://github.com/logstash-plugins/logstash-output-gemfire)
* [logstash-output-jira](https://github.com/logstash-plugins/logstash-output-jira)
* [logstash-output-monasca_log_api](https://github.com/logstash-plugins/logstash-output-monasca_log_api)
* [logstash-output-rados](https://github.com/logstash-plugins/logstash-output-rados)
* [logstash-output-zeromq](https://github.com/logstash-plugins/logstash-output-zeromq)
* [logstash-output-zookeeper](https://github.com/logstash-plugins/logstash-output-zookeeper)

You can rerun `rake generate_plugins_versions` on any other branch( 5.6, etc) to determine which plugins are failing.

Rough proposal:

1) Fix any broken plugins we desire
2) Remove any still-broken plugins from the logstash docs for any affected branches.

Start by running `rake generate_plugins_versions` and inspect the failures in `plugins_version_docs.json` for master and affected branches such as 5.6. Review the linked plugin repositories and the generated documentation entries. Done means the selected broken plugins are fixed or removed from the Logstash docs on every affected branch.

Written by the indexing model from the issue text.