Squash Django migrations (step 1)

This change squashes Django migrations for all Django apps with more
than 3 migrations. See our internal squashing documentation here [0]
and Django's general docs on squashing here [1].

Migration squashing requires multiple steps:

1. Commit squashed migrations, and deploy them.
2. Delete migration files that were squashed, and remove "replaces" in
the squashed migration files. Deploy this change.

This squashing removes some RunPython code that is only compatible with
PostgreSQL; after this squash it will once again be possible to migrate
a SQLite database.

[0] https://cfpb.github.io/consumerfinance.gov/migrations/#squashing-migrations
[1] https://docs.djangoproject.com/en/5.1/topics/migrations/#squashing-migrations

cfgov/v1/util/migrations.py

@@ -1,12 +1,15 @@
 import logging
 import re
 
+from django.utils.deconstruct import deconstructible
+
 from wagtail.blocks.migrations.operations import BaseBlockOperation
 
 
 logger = logging.getLogger(__name__)
 
 
+@deconstructible
 class RegexAlterBlockValueOperation(BaseBlockOperation):
     """Alter a block's value with a regex pattern and replacement"""