Add TxID calculation & New{Layer}Tx Type

New{Layer}Tx methods that compute the `TxID` & `TxType` values from the
transaction values:
- NewL1Tx
- NewL2Tx
- NewPoolL2Tx

Add TxID Scanner & Valuer for database/sql

HistoryDB & L2DB & API packages tests will need to be addapted to the
TestTransaction generation once is done.

Update ethclient contracts & add wdelayer events

* WIP rebase

* Combine both SQL DBs

* API and DB refactor

Update ethclient wdelayer & add auction events

Helper methods for Synchronizer and TX refactor

Idx to 6 bytes (48 bits)

Add TxSelector L2Tx filtering logic

Add GET histroy-transactions endpoint

Add StateDB set & get Idx by EthAddr & BJJ methods

Update common.L1Tx parsers, add test checks

Update ethclient auction & add wdelayer

Change endianness to BigEndian (ಥ﹏ಥ), spec has been updated to achieve
compatibility with js & smart contracts & circuits implementations.

Smart Contracts Data Synchronization

Implement L2DB

Update ethclient

TxSelector GetL2TxSelection & GetL1L2TxSelection integrated with dbs

- GetL2TxSelection & GetL1L2TxSelection integrated with dbs
- Create L1CoordinatorTx of type CreateAccountDeposit when a L2
requires it (and the AccountCreationAuth exists)

Feature/integration

L1Tx Codec

Add contracts & ethclient auction

Feature/compute zkinputs

Implement basic auction funcs in test.Client

Implement first iteration of node

The coordinator implementation has been refactored to allow all the goroutines
to be handled from the node.

Refactor ZKInputs & add struct initialization & add BJJCompressedTo256BigInts util