Introduce `encode-csv`

[TobiasNx]

We can decode csv with metafacture but we cannot encode it.
Would be nice to have an encoder for csv

We can reuse the csv-plugin: https://github.com/metafacture/metafacture-csv-plugin

[TobiasNx]

Usecase scenario: transforming metadata into KBART-format which has a tsv-serialation.

[dr0i]

from #486 (comment):

I tested without options and | encode-csv(includeHeader="TRUE", separator="\t", noQuotes="true") seem to work nicely!

Also added to flux-commands.

[dr0i]

Solved. Closing.