------
- remove dependency `edc_reference`. `edc-reference` maintained a
single table, "edc_reference.Reference", with values needed for
metadata-rules. The table was updated on a `post_save` signal
for CRF/Requisition and other models using the
`ReferenceModelMixin`. By removing `edc_reference`, `edc-metadata` now
directly queries CRF/Requisition models instead of querying model
"edc_reference.Reference". This change has bumped most edc modules. The
dependency was required for a few modules or, as in most cases, just for
tests. The model mixin `ReferenceModelMixin` and the site controller
`site_reference_configs` are no longer required. You may remove from
your app any reference to `edc-reference` and the file
`reference_model_configs`.