++ ugmk: bi postgres database + vault role, mirroring documentations

bi_db with ltree/pg_stat_statements/uuid-ossp extensions in
infrastructure.yaml; bi vault application role and bi-postgres secret
(apps/bi/postgres) in infrastructure-secrets.yaml, same shape as the
documentations app.

infrastructure.yaml

@@ -366,6 +366,21 @@ environments:
           permissions:
             - transmittal_db
 
+      - cluster_id: main
+        database:
+          name: bi_db
+          extensions:
+            - uuid-ossp
+            - pg_stat_statements
+            - ltree
+        user:
+          name: bi
+          password_length: 32
+          password_special: false
+          conn_limit: 20
+          permissions:
+            - bi_db
+
     minio: {}
     buckets: []