Reorganize smart contract types, udate eth tests, etc.

- Move smart contract constants and structs for variables to
  common/{ethrollup.go, ethauction.go, ethwdelayer.go}:
    - This removes repeated code of the structs for variables
    - Allows reusing the constants and variables from all modules without
      import cycles
- Remove unused common/scvars.go
- In common.BlockData, split data from each smart contract into a sepparate
  field (Rollup, Auction, WDelayer).  This affects the structures that til uses
  as output, and HistoryDB in the AddBlockSCData.
- In Synchronizer:
    - Pass starting block of each smart contract as config, instead of
      incorrectly using the genesis block found in the acution constant (which
      has a very different meaning)
    - Use variable structs from common instead of an internal copy
    - Synchronize more stuff (resolve some TODOs)
    - Fix some issues found after initial testing with ganache
- In eth:
    - In auction.go: Add method to get constants
    - Update README to use ganache instead of buidlerevm as local blockchain
      for testing
    - Update env variables and test vectors to pass the tests with the
      deployment in the ganache testnet.
    - Use ethereum keys derived from paths (hdwallet) in testing to avoid
      hardcoding private keys and generate the same keys from a mnemonic used
      in the ganache tesnet.

node/node.go

@@ -107,7 +107,13 @@ func NewNode(mode Mode, cfg *config.Node, coordCfg *config.Coordinator) (*Node,
 		return nil, err
 	}
 
-	sync, err := synchronizer.NewSynchronizer(client, historyDB, stateDB)
+	sync, err := synchronizer.NewSynchronizer(client, historyDB, stateDB, synchronizer.Config{
+		StartBlockNum: synchronizer.ConfigStartBlockNum{
+			Rollup:   cfg.Synchronizer.StartBlockNum.Rollup,
+			Auction:  cfg.Synchronizer.StartBlockNum.Auction,
+			WDelayer: cfg.Synchronizer.StartBlockNum.WDelayer,
+		},
+	})
 	if err != nil {
 		return nil, err
 	}