DNS peer cluster discovery

[qcdll]

I hate the current form of bootnodes: node://da6ea5897f2245346dd0787163512763f26bae9e783adb1ea94053251c1fea0f1324567ac4b1abd2dc3a1cf90a352a7bf7ad11fe7748ca5126e7f2cc5077e1a4@18.236.134.107:38291

I'd rather type something like discovery.quarkchain.io and let it be, it looks devp2p has some new features for this, let's try it out