Script to clean up slug data stored in alternative title

[laritakr]

Once works are migrated to valkyrie resources, we need to clean all slug data out of alternative_title. The slug term is the appropriate location for this.

As part of this, we want to uncomment the index_keys for alternative_title in the resource yaml files, and reindex the updated resources.

Once complete, we can remove the form display: false for alternative_title to allow it to be used.