HistoryDB TXs til test

Add til test l2db

Add Sync stats, and report them in DebugAPI

Test synchronizer reorg

Fix exit table, set delayed_withdrawn in exits

- In exit table, `instant_withdrawn`, `delayed_withdraw_request`, and
  `delayed_withdrawn` were referencing batch_num.  But these actions happen
  outside a batch, so they should reference a block_num.
- Process delayed withdrawns:
    - In Synchronizer, first match a Rollup delayed withdrawn request, with the
      WDelayer deposit (via TxHash), and store the owner and token associated
      with the delayed withdrawn.
    - In HistoryDB: store the owner and token of a delayed withdrawal request
      in the exit_tree, and set delayed_withdrawn when the withdraw is done in
      the WDelayer.
- Update dependency of sqlx to master
    - Last release of sqlx is from 2018 October, and it doesn't support
      `NamedQuery` with a slice of structs, which is used in this commit.

Feature/api db tests til

Swagger review

Cmptbility test for Root StateDB Accounts tree

Swagger Review

Checked with commonjs version:
c8414bd205

Update Account Hash comp to match js version

API state endpoint test

API State RecommendedFee

Process withdrawals in HistoryDB, test withdrawals and vars in sync

API State Metrics

Refactor api pagination

API add get state

StateDB group Fee txs and ZKInputs gen of Fee txs & Update tx bytes parsers methods

Put api DBs into struct

Add DebugAPI to Node, fix StateDB

- Allow starting the DebugAPI from the node via config
- In StateDB:
    - Make checkpoints when ProcessTxs() succeeds
    - Remove extra hardcoded `statedb` path that was redundant
    - Replace hardcoded `[:4]` by `[:]` when parsing idx, which failed because
      idx is 6 bytes length now.
- Extra: In node, use waitgroup instead of `stoppedXXX` channels to wait for
syncrhonizer goroutines to finish.

Move logic to extend til blocks to til

ItemID to uint64 & check timestamp

Account API

Previously, the synchronizer test was extending the output from til to
precalculate many fields to compare it with the synchronizer and BD output.
Since this is useful outside of the syncrhonizer testing: move this
functionality to til via a function that extends the output
(til.Context.FillBlocksExtra).

Also, add new functionality: calculate fee idxs dynamically by setting a user
name, and calculate collected fees.

ZKInputs update:

API add slots endpoints

Check feeAmount overflow in API

Update Synchronizer (node) implementation