Syncs artists csv with relational and object storage

[Ernesto905]

This PR takes a local artists CSV file and adds a sync_artists django admin command, which does the following:

(1) uploads the artist's profile picture and artwork as object storage in digital ocean spaces
(2) populates the Artist and Piece tables, for both local dev (sqlite) or prod (postgres on railway)

[DavidEBest]

This looks really nice! I'll aim to get it tested and merged later this evening.

[DavidEBest]

I think we could clean up the file upload section by using the Django model built in functionality.

config/settings/production.py wires STORAGES['default'] to storages.backends.s3boto3.S3Boto3Storage, driven by generic env vars: S3_ACCESS_KEY_ID, S3_SECRET_ACCESS_KEY, S3_BUCKET_NAME, S3_ENDPOINT_URL, S3_REGION, S3_CUSTOM_DOMAIN. That'll work for Digital Ocean Spaces.When that's active, any ImageField/FileField on any model uploads through it automatically without manual boto3.client() uploads

The pattern to use instead of the manual client:

import requests
from django.core.files.base import ContentFile

resp = requests.get(wix_url, stream=True)
resp.raise_for_status()
_, ext = os.path.splitext(wix_url)
artist.profile_image.save(f"{artist.slug}{ext}", ContentFile(resp.content), save=False)
artist.save()

Django's configured storage backend handles bucket, path (upload_to='artists/profiles/'), and URL generation. artist.profile_image.url comes out correct automatically, so the template changes that swap .url for the raw field value can be reverted. Same pattern would work for Piece if it's changed from a CharField(url) to a FileField.

[Ernesto905]

Cleaned up the file upload section with the pattern you recommended. I ended up moving the object storage config from production.py to base.py, since i'm guess we'll want that function in development as well. Lmk if i can change that back, though