Update and integrate price updater

PriceUpdater:
    - Pass context so that it can be canceled during an update loop
    - Define APITypes to make it explicit which API we are using

cli/node/cfg.buidler.toml

@@ -4,6 +4,11 @@ Explorer = true
 UpdateMetricsInterval = "10s"
 UpdateRecommendedFeeInterval = "10s"
 
+[PriceUpdater]
+Interval = "10s"
+URL = "https://api-pub.bitfinex.com/v2/"
+Type = "bitfinexV2"
+
 [Debug]
 APIAddress = "localhost:12345"