bug: issue when service has not been used for a while

[lucasmenendez]

If the service has not been used for a while and you try to make a request, the server will return an internal server error:

Error: 500 Internal Server Error: error creating the census tree on the census database

If you continue to make requests, the service will start to work properly again.

[lucasmenendez]

these could be the traces related to the error:

2023-08-29T10:20:00.095Z ERR api/censuses.go:188 > error saving the census on the database error="database is locked"
2023-08-29T10:20:10.521Z ERR api/censuses.go:188 > error saving the census on the database error="database is locked"
2023-08-29T10:20:17.18Z ERR api/censuses.go:188 > error saving the census on the database error="database is locked"
2023-08-29T10:20:24.962Z ERR api/censuses.go:103 > holders transaction rollback failed error="sql: transaction has already been committed or rolled back"
2023-08-29T10:23:17.608Z ERR api/censuses.go:188 > error saving the census on the database error="database is locked"