Redo coordinator structure, connect API to node

- API:
	- Modify the constructor so that hardcoded rollup constants don't need
	  to be passed (introduce a `Config` and use `configAPI` internally)
- Common:
	- Update rollup constants with proper *big.Int when required
	- Add BidCoordinator and Slot structs used by the HistoryDB and
	  Synchronizer.
	- Add helper methods to AuctionConstants
	- AuctionVariables: Add column `DefaultSlotSetBidSlotNum` (in the SQL
	  table: `default_slot_set_bid_slot_num`), which indicates at which
	  slotNum does the `DefaultSlotSetBid` specified starts applying.
- Config:
	- Move coordinator exclusive configuration from the node config to the
	  coordinator config
- Coordinator:
	- Reorganize the code towards having the goroutines started and stopped
	  from the coordinator itself instead of the node.
	- Remove all stop and stopped channels, and use context.Context and
	  sync.WaitGroup instead.
	- Remove BatchInfo setters and assing variables directly
	- In ServerProof and ServerProofPool use context instead stop channel.
	- Use message passing to notify the coordinator about sync updates and
	  reorgs
	- Introduce the Pipeline, which can be started and stopped by the
	  Coordinator
	- Introduce the TxManager, which manages ethereum transactions (the
	  TxManager is also in charge of making the forge call to the rollup
	  smart contract).  The TxManager keeps ethereum transactions and:
	  	1. Waits for the transaction to be accepted
		2. Waits for the transaction to be confirmed for N blocks
	- In forge logic, first prepare a batch and then wait for an available
	  server proof to have all work ready once the proof server is ready.
	- Remove the `isForgeSequence` method which was querying the smart
	  contract, and instead use notifications sent by the Synchronizer to
	  figure out if it's forging time.
	- Update test (which is a minimal test to manually see if the
	  coordinator starts)
- HistoryDB:
	- Add method to get the number of batches in a slot (used to detect when
	  a slot has passed the bid winner forging deadline)
	- Add method to get the best bid and associated coordinator of a slot
	  (used to detect the forgerAddress that can forge the slot)
- General:
	- Rename some instances of `currentBlock` to `lastBlock` to be more
	  clear.
- Node:
	- Connect the API to the node and call the methods to update cached
	  state when the sync advances blocks.
	- Call methods to update Coordinator state when the sync advances blocks
	  and finds reorgs.
- Synchronizer:
	- Add Auction field in the Stats, which contain the current slot with
	  info about highest bidder and other related info required to know who
	  can forge in the current block.
	- Better organization of cached state:
		- On Sync, update the internal cached state
		- On Init or Reorg, load the state from HistoryDB into the
		  internal cached state.

common/ethauction.go

@@ -23,6 +23,28 @@ type AuctionConstants struct {
 	GovernanceAddress ethCommon.Address `json:"governanceAddress"`
 }
 
+// SlotNum returns the slot number of a block number
+func (c *AuctionConstants) SlotNum(blockNum int64) int64 {
+	if blockNum >= c.GenesisBlockNum {
+		return (blockNum - c.GenesisBlockNum) / int64(c.BlocksPerSlot)
+	}
+	return -1
+}
+
+// SlotBlocks returns the first and the last block numbers included in that slot
+func (c *AuctionConstants) SlotBlocks(slotNum int64) (int64, int64) {
+	startBlock := c.GenesisBlockNum + slotNum*int64(c.BlocksPerSlot)
+	endBlock := startBlock + int64(c.BlocksPerSlot) - 1
+	return startBlock, endBlock
+}
+
+// RelativeBlock returns the relative block number within the slot where the
+// block number belongs
+func (c *AuctionConstants) RelativeBlock(blockNum int64) int64 {
+	slotNum := c.SlotNum(blockNum)
+	return blockNum - (c.GenesisBlockNum + (slotNum * int64(c.BlocksPerSlot)))
+}
+
 // AuctionVariables are the variables of the Auction Smart Contract
 type AuctionVariables struct {
 	EthBlockNum int64 `json:"ethereumBlockNum" meddler:"eth_block_num"`
@@ -32,6 +54,8 @@ type AuctionVariables struct {
 	BootCoordinator ethCommon.Address `json:"bootCoordinator" meddler:"boot_coordinator" validate:"required"`
 	// The minimum bid value in a series of 6 slots
 	DefaultSlotSetBid [6]*big.Int `json:"defaultSlotSetBid" meddler:"default_slot_set_bid,json" validate:"required"`
+	// SlotNum at which the new default_slot_set_bid applies
+	DefaultSlotSetBidSlotNum int64 `json:"-" meddler:"default_slot_set_bid_slot_num"`
 	// Distance (#slots) to the closest slot to which you can bid ( 2 Slots = 2 * 40 Blocks = 20 min )
 	ClosedAuctionSlots uint16 `json:"closedAuctionSlots" meddler:"closed_auction_slots" validate:"required"`
 	// Distance (#slots) to the farthest slot to which you can bid (30 days = 4320 slots )
@@ -48,7 +72,7 @@ type AuctionVariables struct {
 func (v *AuctionVariables) Copy() *AuctionVariables {
 	vCpy := *v
 	for i := range v.DefaultSlotSetBid {
-		vCpy.DefaultSlotSetBid[i] = new(big.Int).SetBytes(v.DefaultSlotSetBid[i].Bytes())
+		vCpy.DefaultSlotSetBid[i] = CopyBigInt(v.DefaultSlotSetBid[i])
 	}
 	return &vCpy
 }