Instantiate missing StackerDBs in the 3.0 hard fork

[netrome]

When we introduced support for persisting DKG shares in #4659 this requires two new StackerDBs to be instantiated by deploying the signers-0-13 and signers-1-13 contracts. However, since the signer smart contracts were already deployed in epoch 2.5 before this PR got merged, these contracts were never instantiated.

To patch this, we must explicitly deploy these contracts before the 3.0 hard fork.

Definition of Done

The stacks node deploys the signers-0-13 and signers-1-13 contracts when 3.0 activates.