feat(cosmwasm): add subcommand to register a chain on ITS hub through governance proposal

[eguajardo]

See README for more details.

Example use and encoded proposal output:

node cosmwasm/submit-proposal.js its-hub-register-chains avalanche-fuji sui-test2 -t "Proposal title" -d "Proposal description" --deposit 100000000 --runAs axelar18ex0nm9peqdc9va0kekv3ha2cqx9pvrfj35shy

Encoded /cosmwasm.wasm.v1.ExecuteContractProposal: {
  "title": "Proposal title",
  "description": "Proposal description",
  "runAs": "axelar18ex0nm9peqdc9va0kekv3ha2cqx9pvrfj35shy",
  "contract": "axelar10jzzmv5m7da7dn2xsfac0yqe7zamy34uedx3e28laq0p6f3f8dzqp649fp",
  "msg": {
    "register_chains": {
      "chains": [
        {
          "chain": "avalanche-fuji",
          "its_edge_contract": "0x144c3d7A5f5198EF3B46A8258b35E903cf197A66",
          "truncation": {
            "max_uint": "115792089237316195423570985008687907853269984665640564039457584007913129639935",
            "max_decimals_when_truncating": 255
          }
        },
        {
          "chain": "sui-test2",
          "its_edge_contract": "0xc848bdd1dc546487c43f3d60ec089945644e17ffb52b0a667884dc884d6666a1",
          "truncation": {
            "max_uint": "18446744073709551615",
            "max_decimals_when_truncating": 6
          }
        }
      ]
    }
  },
  "funds": []
}

https://axelarnetwork.atlassian.net/browse/AXE-6696