list input of qc functions can be provided by the user with the config file

[Geet-George]

For the user to be able to provide a list of qc functions, this will have to be incorporated in a pipeline which calls the apply_qc_checks function for each Sonde instance as part of the QC.

• create a data-processing pipeline #49
• incorporate user's QC functions into this pipeline

[Geet-George]

Instead of incorporating the user's QC functions into the pipeline, the user can provide the list of QC checks to run as part of the function argument for the apply_qc_checks function.

[Geet-George]

Closing this as it is now implemented in #46