Integrate multisig

[samuelmanzanera]

This PR supports multisig for bridge contracts management.
It adds two commands:

• deploy_multisig: convert the master chain into a multisig
• get_router_address: to get the address of the router from the keychain service derivations

To test this PR:

• Init the keychain: node dex init_keychain
• Deploy the factory: node dex deploy_factory
• Change the master to multisig: node dex deploy_multisig
• Get the router address: node dex get_router_address
• Fund this address (either via multisig or faucet)
• Deploy the router without the initial funding: node dex deploy_router --without_funding
• To update the pool with multisig: node dex update_router --with_multisig
• Confirm the multisig transaction
  • Through the UI
  • Using the CLI: node multisig.js confirm-transaction

Others update commands have been updated as:

• update_protocol_fee
• update_pools
• update_lp_fee
• update_farms
• update_farm_dates