Replace `logrus` with `log/slog`

[chr-fritz]

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Is your feature request related to a problem? Please describe. Currently knx-exporter uses logrus for structural logging. Since golang 1.21 integrated a new logging library (see https://pkg.go.dev/log/[email protected]) directly into the standard library it meight be better in the future to switch to this new logging library as most of the other dependencies meight also switch to log/slog.