Update internal logging to expose the slog logger to components

[wildum]

Context:

• Update mysqld_exporter to v0.16.0 #1643
• exporter-toolkit has changed the signature of web.ListenAndServe to use slog, meaning that a bunch of exporters in Alloy are suddenly impacted and will need to be updated

We use slog but we are passing a go-kit logger interface to the components for compatibility. Ideally we would like to be able to pass the slog logger to the components that can support it.

The solution might be to pass our internal logger down to the components because it supports both go-kit and slog but it would require to implement the log.With equivalent.

The blast radius is important with this change.