Connext router fees safety net

[BitcoinOG]

The connext router node now supports fees. Similarly to lightning where we currently have a hardcoded 3% limit in opendexd, we want to add this hardcoded safety net for connext routed payments.

What needs to be done: opendexd calls the request quote endpoint (routing fees on connext are requested first) and calculate the percentage and accept if <=3% and reject if >3%