refactor extract_timeseries_profiles to two functions?

[smwoodman]

Hi again @jklymak

When creating profile files for IOOS, we want to a couple things differently from extract_timeseries_profiles. For instance, our id attribute doesn't include the glider serial number, and we have different sensors and thus more variables that those in to_fill for which we want to make _qc ancillary variables.

These are too group-specific for pyglider, but it would be great if there was a way to both use the extract_timeseries_profiles processing logic/code, while also not having to read in each profile nc file to do our group-specific post-processing.

So, would it feel ok to you to pull out the profile creation into another function, which is called by extract_timeseries_profiles? The behavior of extract_timeseries_profiles would stay the same, and those of us that want to add group-specific processing could use the intermediate function.