Problem: v16 octez binaries don't like starting from protocol Ps9mPmXa

Solution: start from ProtoGenesis instead. Set first block fitness to 0
in `run-local-chain.sh` and `voting.py` to reduce startup delay.

For reference, setting activation time far in the past doesn't work,
because:

- baker daemon will wait for round timeout
- even if we forge baking, consequent blocks are timestamped in the
  past, which messes with node synchronization