On the Circuits uses the name `nTx` (and on the tests `maxTx`), but
Contracts `maxTx`. On Go we had both variables, but really only used
one, now at Go we use `MaxTx` to refer to the maximum number of
transactions.

- Add TestZKInputsEmpty circom test vectors
- Fix ZKInputsHash OldLastIdx bytearray

- Update IntermediateState FinalAccFee values to fit in the Circom circuit expected inputs
- Add ZKInputs generation test with transactions generated by Til
(TestZKInputs6)
- BatchBuilder: remove redundant MakeCheckpoint call

- Separate ZKInputs tests at StateDB package
- Small fix at ZKInputs generation FeeIdxs length
- Fees related parameters at ZKInputs works properly
- Add ZKInputs generation test with fees (`TestZKInputs1`), which output
has been tested with circom to ensure compatibility

- Add SignatureConstant to L1Tx.TxCompressedData
- ZKInputs generation works initial version working and compatible with circom Hermez circuit
    - Lots of small updates for circuits compatibility
- Update version (with new changes) of `go-iden3-crypto` & `go-merkletree`

- Add InvalidData flag to L1Tx
- Add BytesDataAvailability to L1Tx
- Update ZKInputs & HashGlobalInputs to last spec of the protocol
(massive migrations)
- TxProcessor check correctness of L1Txs

Compatible with hermeznetwork/commonjs v0.0.4
(c345239bba)

- Add L1Tx TxCompressedData method
- Add PoolL2Tx TxCompressedDataV2 method
- Update ProcessTxs logic
- Add ZKInputs Intermediate States & Fee parameters calculation

Add HashGlobalInputs for ZKInputs compatible with js & circom circuits version.

Compatible with hermeznetwork/commonjs at version: c6a1448db5
(c6a1448db5)

- Add ZKInputs parser to JSON
- Update ProcessTxs to last go-merkletree version changes
- Add StateDB test to generate ZKInputs to check inside a circom circuit
- Small fix at Til CoordinatorTx.LoadAmount=0

- Update StateDB ProcessTxs fees collection
- Update ProcessTxs tests to last StateDB & Til changes
- Til Blockchain L2Txs remove Nonce generation, update tests accordingly
- Update Til Set to test fees

Refactor ZKInputs & add struct initialization & add BJJCompressedTo256BigInts util

* update zkInputs

* ZKInputs clean uncomment use nolint

Co-authored-by: arnaucube <root@arnaucube.com>

- gofmt - Gofmt checks whether code was gofmt-ed. By default this tool runs
  with -s option to check for code simplification
- goimports - Goimports does everything that gofmt does. Additionally it checks
  unused imports
- golint - Golint differs from gofmt. Gofmt reformats Go source code, whereas
  golint prints out style mistakes
    - checks the uncommented exported functions & types

Update the code to fix the lint checks.

- Update GHA lint.yml increasing timeout time to avoid GHA Lint errors
- Update common.BatchNum & common.Idx & common.Nonce usage in StateDB
- Add abstraction method of processTxs to StateDB
    - Which will be used by Synchronizer & BatchBuilder