Add HDFS Support and RFC 5655

[r4ravi2008]

• Ability to write Vflow json data directly to HDFS.
• Ability to write capture and store IPfix messages in RFC 5655 file format(https://tools.ietf.org/html/rfc5655).

What do you think about adding these new features? Do you think these features are within the context and scope of this repo? I may be able to contribute on this front.

[mehrdadrad]

I like both and I think they should be developed under vflow/consumers
Already we have clickhouse, memsql and spark sample consumers.
Any help would be appreciated