Feature Request: Add flag to be able to disable leader election

[slimm609]

By default leader election is always on even when the replica is 1, there is no option to disable leader election. This means that API calls to perform leader election are happening all the time when it is never needed with a replica of 1.

the common way this is handled is having a flag to turn it on. Cert-manager does not use leader election by default with a single replica however trust-manager does. This would be good to align trust-manager with the way cert-manager handles it.