Make LeaderElection accessible

[kuritka]

The LeaderElection controller property is hardcoded. Currently set to false.

• Make LeaderElection accessible via environment variable (and if necessary, provide another implementation to make the leader election work)
• Provide tests to prove that the leaderelection mechanism works

	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
		Scheme:             runtimescheme,
		MetricsBindAddress: config.MetricsAddress,
		Port:               9443,
		LeaderElection:     false, // <---- config.LeaderElection
		LeaderElectionID:   "8020e9ff.absa.oss",
	})

[ytsarev]

elastic/cloud-on-k8s#3632 (comment) might relevant

[somaritane]

Parking this one.