Make use of secret-manager while using weather-dl for license keys.

[dabhicusp]

As part of our current data download process for the weather-dl, we are not using secret-manager services. This poses a potential security risk, as the sensitive configuration data stored in the config file could be inadvertently leaked, resulting in public access to our API keys and other credentials.

To ensure the security of our licenses and sensitive configuration data, we should integrate the Secret Manager service into the weather-dl application. This will allow us to securely manage and retrieve API keys, URLs, and other credentials used during the data download process.

[alxmrs]

Duplicate of #12. Either way, I'm really happy to see this change in weather-dl -- thanks for creating the issue (and working on this).