Trusted cluster resource name == cluster name

[klizhentas]

Description

It is very confusing that trusted cluster resource name could be different from the actual cluster name, so we will migrate the existing trusted cluster resources to be named as remote clusters and will enforce the trusted cluster resource name to be == to cluster name.

As a part of this we can relax specifying trusted cluster resource name during creation, because we can auto name the resource.

If user creates

kind: trusted_cluster
spec:
   dial_addr: 
   token: 

the name will be auto assigned from the cluster name.

If users do stick a name there print a warning that name will be ignored.