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

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

Update log package with fields & file log, and update constants in the
repository code to be MixedCase.

resolves #91, resolves #92, resolves #95

- 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.

Add linter checks to GHA & Fix code to pass lints.
The linters added are:
- whitespace: Tool for detection of leading and trailing whitespace
- gosec: Inspects source code for security problems
- gci: Gci control golang package import order and make it always deterministic
- misspell: Finds commonly misspelled English words in comments
- gomnd: An analyzer to detect magic numbers

The file utils/utils.go is excluded from the checks of gomnd, as uses magic numbers through the code

Add Coordinator goroutines & channels processes
- Add Coordinator goroutines & channels
- Add Coordinator test to debug batches
- Add MakeCheckpoint call after BatchBuilder BuildBatch process
- Update ethClient BlockByNumber to return hermez/common.Block instead of go-ethereum/core/types.Block

Add StateDB tx processor tests using tx test generators:
- update statedb/ tx processors
- add statedb tx processors tests

Update tx testing generation:
- add new batch lexic to tx-test language
- add coordinatorL1Txs generation to tx-test
- add SetTest0 code to generate test L1&L2 transactions

Add test-lang Fee & ForceExit option