server: implement backoff retry login for db connection

[Teja2045]

https://github.com/vitwit/resolute/blob/5f79032361f9435b90d405d7fba7431cb5b55e8c/server/server.go#L42-L45

The db connection is failing after trying only once. This is creating issue when running docker compose file.

Server image depends on db image

when running docker compose up, server won't wait till db in initialized.

It would be better if we TRY TO RECONNECT a few more times before panicking.