Migrate from password to OAuth

[snarfed]

Includes migrating the current Feed datastore entities to oauth_dropins.bluesky.BlueskyAuth. Here's how I've done that so far:

class Feed(ndb.Model):
    handle = ndb.StringProperty(required=True)
    password = ndb.StringProperty(required=True)
    session = JsonProperty(default={})

Feed.query().count()

for feed in Feed.query():
  if feed.session:
    did = feed.session['did']
    BlueskyAuth(id=did, password=feed.password, session=feed.session,
      user_json=json.dumps({'did': did, 'handle': feed.handle})
      ).put()

[snarfed]

Done!

[snarfed]

Reopening, I need to figure out a better answer for token lifetime. Evidently Bluesky OAuth doesn't do infinite lifetime tokens. Public clients are limited to 2w refresh, and confidential clients that sign their request with JWTs have 6 mos. Ugh. https://atproto.com/specs/oauth#tokens-and-session-lifetime

[snarfed]

Simplest first step here is probably to revert back to app passwords. 😕

[snarfed]

Done.