Allow relay parameters to be configurable on a per relay basis #40
Description
Rationale
Currently you can specify validation_blacklist which applies to all relays. This means that you can either configure your builder to either mostly work with censorious relays or completely work with censorious relays.
When you do not specify a validation_blacklist your builder may submit bad requests to censorious relays. It will continue to submit bad requests to the censorious relay until the transaction in question is removed from the mem pool.
When you do specify a validation_blacklist your builder will filter requests to open relays and will likely never be selected by an open relay.
Implementation
It's not realistic to run simulations for every relay. A simple approach could be to filter transactions just before submission to the relay. This will mean that submissions to open relays will be more profitable to validators and block builders. Whilst still serving up blocks to validators that are connected to censorious relays.