Collect common functions/interfaces in separate package?

[tsalo]

There are some steps that are probably going to be fairly common across fMRIPost workflows. I am trying to decide if those functions and interfaces should go in a separate package (e.g., nipostflows) or if I should just try to get them in niworkflows.

Starting a list:

• Motion filtering to respiration-related noise
• Interface to measure functional connectivity inflation over the course of the run
• Interface to calculate QC-FC measures