Simple Timeout fixes of the current View Change protocol

There are problems in existing View Change protocol (see INDY-1296 and INDY-1303).
Although the correct way to deal with it is to implement PBFT View Change, we can try to have some fixes which can improve stability of the View Change.

Possible fix (with options):

1. do not process any PrePrepares and Prepares above prepared_certificate.
2. [optional]: send COMMITs to all nodes ot make sure they order till their prepared certificates.
3. get rid of the logic on exiting on multiple rounds of catch-up without new txns caught-up.
4. [optional]: we may have some positive timeout for ordering till last_prepared
5. we may continue doing catch-ups all the time, or just do one catch-up at the end, or don't do them at all for simplicity.