TxSel avoid L1CoordTx for L2Tx that have a L1UserTx in the frozen queue

Add package level documentation for db, historydb, l2db, api, apitype…

For the L2Txs of TransferToEthAddr & TransferToBJJ for a not-yet
existing accounts, in the TxSelector check if L2Tx receiver account will
be created by a L1UserFrozenTxs (in the next batch, the current frozen
queue). In that case, the L2Tx will be discarded at the current batch,
even if there is an AccountCreationAuth for the account, as there is a
L1UserTx in the frozen queue that will create the receiver Account.  The
L2Tx is discarded to avoid the Coordinator creating a new
L1CoordinatorTx to create the receiver account, which will be also
created in the next batch from the L1UserFrozenTx, ending with the user
having 2 different accounts for the same TokenID.
The double account creation is supported by the Hermez zkRollup
specification, but it was decided to mitigate it at the TxSelector level
for the explained cases.

instrumenting the application

Faster synchronization by fetching only block headers

fix the invalid goarch build

Add configuration option to choose recommended fee strategy, and add …

Generating automatically releases with Goreleaser

Document synchronizer, node and coordinator

add AGPLv3 License

Add minimum documentation of serveapi command

fix the application initialization flags

Bound the filter of init SC events by blocks

When querying the init event for each smart contract, bound the search from
block genesis-24h to block genesis.  Otherwise, this query in geth synced to
mainnet takes too long.

Move apitypes & stateapiupdater into api dir

Add API versioning

Add account_state view

Update TxSel selection to prioritize the forgable

Previous to this commit, there were cases where being
len(nonForgableL2Txs)>maxL2Txs and nonForgableL2Txs have bigger fee than
forgableL2Txs, the forgableTxs where never forged, neither the
nonForgableTxs.  Now, the TxSelector first forges the forgableTxs (which
are forgable for the initial state of the accounts (balances & nonces),
and then the nonForgableL2Txs, which may be unblocked once the forgable
ones have been processed.

API change names and add poolLoad, add maxFeeUSD

Add pending L1 txs to API

Add config parameter  ForgeOncePerSlotIfTxs

Create a Makefile for build using -ldflags and useful commands

Store *big.Int as DECIMAL in sql

Not count txs marked as external_delete to reach MaxTxsPool

Fix average transaction fee calculation

Fix API /state collected fees unmarshal

Fix Synchronizer not setting slot.ForgerCommitment to true