output aggregation

[buhman]

Some things that are used with hubble produce report-like output.

danwith requested native multi-environment output aggregation support. This "output aggregation" mode has a few sub-features:

• the environment header is not interleaved with command output
• output from the command is parsed and aggregated
  • an example would be aggregating multiple CSVs, with correct header handling
    • it would be sane to make this the default aggregation mode as well
• I'm not sure if this should be limited to "aggregating things with fields"
  • if it is, maybe hubble could also inject fields into the aggregated output, like environment name.
    • the field name could also be configurable

@thrawn01 I'd like your blessing to implement this.

[buhman]

I think we established that if this is implemented, it should be implemented as an extension to hubble, and not as an integrated hubble feature.

[thrawn01]

+1 as an extension, sounds really cool