Improve the switch off replica logic to do it after InstanceChange quorum

A backup replica should be switch off after quorum of INSTANCE_CHANGE messages on backup instance.

Acceptance criteria:

• A strategy done in INDY-1682 should result in sending a special INSTANCE_CHANGE about instance change on backup instance X
• Once node got a quorum (n-f) of instance changes on backup instance X, it switches off the replica (INDY-1680)
• add tests to check correct replica switch off

• testing perfomance changes (shouldn't be worse then in task INDY-1682) after disconnect or degraded a backup primary node.

• testing memory consumption (should be better then in task INDY-1682)