Convert petfinder sync and rescue groups sync code to use secrets manager

petfinder_sync/petfinder_sync/petfinder_sync.py
sync_to_rescue_groups/sync_to_rescue_groups/sync_to_rescue_groups.py

Currently uses a config.ini file.

Convert to use secrets manager via boto to grab the needed keys.

See wordpress_pet_sync/wordpress_pet_sync/wordpress_pet_sync.py for working example. Lambda also needs permission for secrets manager.