Plugins currently use a couple configuration methods to set up field
data for the class. This seems superfluous. This change moves these
configuration steps into the init method so plugin classes can ingest
data as kwargs.
Here is an example of how the change will be implemented in plugins:
https://review.opendev.org/#/c/670171/
Change-Id: Ib26636f1eb4146902ee801af5bcce53d137be2ad