In the metrics query, the estimatedTimeToForgeL1 was probably not being read
from the SQL query because it contained upper case letters, and in PostgreSQL
when identifiers are not double quoted they are case insensitive:
https://stackoverflow.com/a/20880247

Update usage of `*babyjub.PublicKey` to `babyjub.PublicKeyComp`
- when the key is not defined, internally is used `babyjub.EmptyBJJComp`, which is a `[32]byte` of zeroes of type `babyjub.PublicKeyComp`
- the API continues returning `nil` when the key is not defined

Related to 445f26ec9f

- 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)

* WIP: rebase

* Make nullable fields use pointers

* WIP rebase

* Combine both SQL DBs

* API and DB refactor