1. Startup phase is a condition when there is only one section with the empty prefix.
2. Actual split will be a separate task, so don’t actually split: this startup phase will always be in force for all tests.
3. Startup phase details:
during the startup phase, every Live block becoming valid has the age of 5.
don't relocate during startup phase.
resource Proofing is disabled via same mechanism as currently for mock crust in master
joining nodes to be given target address range for their public keys so that the section is balanced. Target address range to be calculated as per the simulator.