Change logger output

[liornoy]

Currently, the logger is always referencing "level.go:63" as the caller.
Also, it is printing the nanosecond with each timestamp
making the logs noisy.

This commit fixes those issues.
fix #1324

Before:

{"caller":"level.go:63","controller":"ConfigReconciler","level":"info","start reconcile":"/kind-worker2","ts":"2022-05-01T15:19:34.80207407Z"}
{"caller":"level.go:63","controller":"ServiceReconciler - reprocessAll","level":"info","start reconcile":"metallbreload/reload","ts":"2022-05-01T15:19:34.802084883Z"}
{"caller":"level.go:63","controller":"ConfigReconciler","event":"force service reload","level":"info","ts":"2022-05-01T15:19:34.802192555Z"}
{"caller":"level.go:63","controller":"ConfigReconciler","event":"config reloaded","level":"info","ts":"2022-05-01T15:19:34.802207787Z"}
{"caller":"level.go:63","controller":"ConfigReconciler","end reconcile":"/kind-worker2","level":"info","ts":"2022-05-01T15:19:34.802215278Z"}
{"caller":"level.go:63","controller":"ConfigReconciler","level":"info","start reconcile":"/kind-worker","ts":"2022-05-01T15:19:34.8022348Z"}
{"caller":"level.go:63","controller":"ServiceReconciler - reprocessAll","end reconcile":"metallbreload/reload","level":"info","ts":"2022-05-01T15:19:34.802268998Z"}

After:

{"caller":"node_controller.go:42","controller":"NodeReconciler","level":"info","start reconcile":"/kind-worker2","ts":"2022-05-01T15:39:11Z"}
{"caller":"bgp_controller.go:330","event":"nodeLabelsChanged","level":"info","msg":"Node labels changed, resyncing BGP peers","ts":"2022-05-01T15:39:11Z"}
{"caller":"speakerlist.go:271","level":"info","msg":"triggering discovery","op":"memberDiscovery","ts":"2022-05-01T15:39:11Z"}
{"caller":"config_controller.go:48","controller":"ConfigReconciler","level":"info","start reconcile":"metallb-system/memberlist","ts":"2022-05-01T15:39:11Z"}
{"caller":"node_controller.go:61","controller":"NodeReconciler","end reconcile":"/kind-worker2","level":"info","ts":"2022-05-01T15:39:11Z"}
{"caller":"service_controller_reload.go:98","controller":"ServiceReconciler - reprocessAll","end reconcile":"metallbreload/reload","level":"info","ts":"2022-05-01T15:39:11Z"}

[sabinaaledort]

/lgtm

[fedepaol]

LGTM, thanks!