Add logging

[orhun]

Is your feature request related to a problem? Please describe.

nvd_cve crate shows some logs regarding the fetched feeds but flawz do not use any logging.

Describe the solution you'd like

We can initialize logging via crates env_logger or tracing crates and log the following information at startup:

• Database location (debug)
• Fetched feeds (info)
• Database URL
• And so on.

Describe alternatives you've considered

None.

Additional context

Just for context, nvd_cve logs the feed info as follows: