* Prevent initializing clusters multiple times
Signed-off-by: Lauri Nevala <lauri.nevala@gmail.com>

* Do not expose intializing to cluster state
Signed-off-by: Lauri Nevala <lauri.nevala@gmail.com>

* Convert initializing to observable and ensure it is set to false after init
Signed-off-by: Lauri Nevala <lauri.nevala@gmail.com>