autoregistration: allow bootstrap node to override locality
During testing of VM autoregistration, we discovered that it is not
possible to override the WorkloadGroup template's locality from the
bootstrap node locality. The core issue is that istiod initializes the
proxy struct from the bootstrap node before passing it to the
autoregistration controller; however, the node's locality is not set on
the proxy at that time. This is fixed by passing the bootstrap node
along to autoregistration code in addition to the proxy.
