Switch to using abbreviated authors

[joverlee521]

Because of nextstrain/auspice#1846, any filters with the full authors field will not work via URL params. The rabies build can switch to using the abbreviated authors field to avoid this issue.

Possible solutions

1. Update ingest config to remove the abbr_authors_field so that the author values are updated in place. The phylogenetic workflow can continue to use the authors field without any changes.
2. Replace the author fields with abbr_authors in the auspice_config.json.
3. Add abbr_authors to the auspice_config.json, which will allow both the abbreviated authors and full authors list to be displayed in the tree.