Rename input-csv for clarity

[Robsteranium]

The components and cube pipeline both ask for an input-csv. We can make this argument more descriptive in each case to avoid confusion.

I'd be inclined to name it after the type of resource that's in each row of the csv, as follows:

pipeline	row type	parameter name
components-pipeline	component	components-csv
codelist-pipeline	code	codes-csv
cube-pipeline	observation	observations-csv

Note that this would mean renaming the codelist-csv to codes-csv for consistency with the other two changes. This would also be consistent with #96, given that we might one day want a table of codelists or codelists-csv!

There might indeed be an argument for renaming the pipelines accordingly (codes-pipeline and observations-pipeline).

[Robsteranium]

Since the cube-pipeline produces more than just observations, we shouldn't rename that to observations-pipeline.