- Add config parameter `Coordinator.L2DB.MinPriceUSD` which allows rejecting
txs to the pool that have a fee lower than the minimum.
- In pool tx insertion, checking the number of pending txs atomically with the
insertion to avoid data races leading to more than MaxTxs pending txs in the
pool.
- In tx_pool, add a column called `external_delete` that can be set to true
externally. Regularly, the coordinator will delete all pending txs with this
column set to true. The interval for this action is set via the new config
parameter `Coordinator.PurgeByExtDelInterval`.
- In tx_pool, add a column for the client ip that sent the transaction. The
api fills this value using the ClientIP method from gin.Context, which should
work even under a reverse-proxy.
Last db view is an opened pebble db which always contains a checkpoint from the
last batch. Methods to access this last batch are thread safe so that views of
the last checkpoint can be made anywhere and with a consistent view of the
state.
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
