feat: add indexer for git (#338)

- reuse the database for the indexer

Reviewed-on: https://git.query.consul/unkinben/puppet-prod/pulls/338

hieradata/roles/infra/git/server.yaml

@@ -105,3 +105,5 @@ gitea::custom_configuration:
   cache:
     ADAPTER: redis
     HOST: "redis+sentinel://gitea-redis-replica-prod.service.consul:26379/1?master_name=au-syd1&password=%{hiera('gitea_redis_pass')}&sentinel_password=%{hiera('gitea_redis_pass')}"
+  indexer:
+    ISSUE_INDEXER_TYPE: db