Adds provider address in preconfirmation for UX through bidder api

[ckartik]

• Resolves issue Nit UX Improvement: Add Provider Address in API Response #172
• Adds provider identity to bidder API

krishchopra@krishs-mbp ~ % curl -X POST http://localhost:13523/v1/bidder/bid \
-d '{
  "txHash": "91a89B633194c0D86C539A1A5B14DCCacfD47094",
  "amount": 20000,
  "blockNumber": 899099
}'
{"result":{"txHash.... "providerAddress":"0x48ddC642514370bdaFAd81C91e23759B0302C915"}}

With Topology

{
  "self": {
    "Addresses": [
      "/ip4/127.0.0.1/tcp/13522",
      "/ip4/192.168.86.247/tcp/13522"
    ],
    "Ethereum Address": "0x4fE8fDf4cE9a85C1e15433751fd4bB748Ef79CF7",
    "Peer Type": "bidder",
    "Underlay": "16Uiu2HAm9kp4BCHqWr6zbSqvF1vNddKLqorHtrDvTVq4dTLhPZ6o"
  },
  "connected_peers": {
    "providers": [
      "0x48ddc642514370bdafad81c91e23759b0302c915"
    ]
  },
  "blocked_peers": null
}

Showing the provider address is correctly sent back over the bidder api