Create snmptrap filter plugin

[skoudis]

The snmptrap input plug integrates with the MIB.yaml file for many vendors in order to translate the OID data.

Currently the only way to translate the OID data is if the snmptrap message is received by a logstash listener and this input plugin. We are extracting the snmptrap messages from splunk via query and shipping via http post in json format to Logstash listening via the http input plugin. This prevents the decoding of the OID data with the snmptrap plugin. Because our customers use splunk as the primary log collection tool, we cannot change how we get the snmptrap message data. Also having the snmptrap plugin as a filter plugin support testing of configurations using stdin input.

Please evaluate this request and if possible create a new snmptrap filter plugin.