In anticipation of the afw.Filter refactor (DM-26259) it has been noted that DCR is the only code making use of wavelength information stored in the filter definition. In order to simplify that transition and in light of needing to use the true filter transmission curves (DM-13668) eventually, I should temporarily move wavelength information to a new location and remove dependence on afw.Filter. That new location could be in the config of the Tasks, which in the future could be used as a user override even when the true transmission curves are available.