Show badges for Alumni and Advisors

Right now we don't show badges for alumni and advisors due to the nature of it requiring an ldap sync.

1. Call LDAP on first misc signatures of a packet to collect roles
2. On subsequent signatures, check to see if they've signed another packet, if so, pull roles from previous signature to avoid ldap call
3. Update `ldap-sync` to update roles on all transitions

(We may also want to move in the schema a `roles` table so that we only pull the data once per person overall)

Start by tracing the packet signature handling and the `ldap-sync` entry point mentioned in the issue. Confirm how roles are currently obtained and persisted, then verify that first signatures query LDAP, later signatures reuse prior roles, and role transitions update all affected records; any schema change should be evaluated separately.

索引モデルが issue の本文から書いたものです。