High: nfsserver: Keep statd directories synced with ha backup

This reduces the complexity of the statd/sm and statd/sm.ha directories.
Right before shutdown we sync statd/sm with statd/sm.ha so client statd
info will failover with the server. This prevents us from having to manage
the third backup folder, statd/sm.ha.save.
High: nfsserver: introducing nfs_no_notify option for suppressing reboot notifications

There is a use-case for nfsserver that requires NFSv3 reboot
notifications to be posponed until after both the nfs server
and floating IP have been started. The nfs_no_notify option
allows us to suppress the reboot notifications until after
the floating ip has started.
High: nfsnotify: Introducing nfsnotify agent for decoupling NFSv3 reboot notifications out of nfsserver