Refactor category-cryptocurrency (#350)

* Remove one-domain lists

* Move domains into category-cryptocurrency

data/category-cryptocurrency

@@ -2,24 +2,25 @@
 
 include:asproex
 include:binance
-include:bitbank
-include:bitcoin
-include:bitfinex
 include:bitflyer
-include:bitmex
-include:bitquick
 include:bitsquare
-include:bitstamp
-include:bittrex
-include:btcbox
-include:cex
-include:coinbase
 include:coinone
-include:dogecoin
 include:ethereum
 include:huobi
-include:kraken
 include:localbitcoins
-include:okex
-include:paxful
 include:zb
+
+bitbank.cc
+bitcoin.org
+bitfinex.com
+bitmex.com
+bitquick.co
+bitstamp.net
+bittrex.com
+btcbox.co.jp
+cex.io
+coinbase.com
+dogecoin.com
+kraken.com
+okex.com
+paxful.com