[Improvement] Remove other resource (except lease) options for leader election

[unmarshall]

Feature (What you would like to be added): Druid offers several resource types to use for leader election and makes it configurable via LeaderElectionResourceLock command line argument. Current set of resource types supported:

• endpoints
• configmaps
• leases
• endpointsleases
• configmapsleases

We should remove this option now and just default it to lease. This change has also been done for all gardener components requiring leader election

Motivation (Why is this needed?): Leases is the default and recommended resource type to be used for leader election.

Approach/Hint to the implement solution (optional): We should deprecate LeaderElectionResourceLock only and always default it to leases. In g/g where etcd-druid is provisioned we need to make changes so that this command line parameter if used is no longer used.