Looper should use hook/plugin system to construct pipestat config files

[donaldcampbelljr]

          Will proceed with having Looper construct a new pipestat config file from a given pipestat config file AND the pipeline interfaces. Looper will use that config file to construct pipestat manager objects. Future work will investigate using a `pre-project` hook to construct this namespace and associated config file.

Originally posted by @donaldcampbelljr in #412 (comment)

[donaldcampbelljr]

Similar to the pre_submission hooks that are evaluated before writing the submission script, it would be nice to move the construction (and updating) of the pipestat namespace to use a hook, perhaps at the project level. This pipestat namespace would be assembled from a given pipestat config (provided within the looper config file) and any pipestat relevant information contained within a pipeline interface file. This namespace would be used to check if pipestat is properly configured as well as for creating the relevant pipestat manager objects.

Challenges:

• currently we have a pre_submission hook that updates the namespaces immediately before writing our submissions script. These namespaces are updated within this function. The pipestat namespace is created at this point in the program. We would need to move the creation of the pipestat namespace to earlier in the program.

[donaldcampbelljr]

Related to but an improvement on #411

[donaldcampbelljr]

With the most recent refactoring work, I believe this is no longer a relevant approach. Closing for now.