fix(Documentation): remove outdated note about the registry + etcd
fix(Documentation): remove outdated note about the registry + etcd

This note was probably from when fleet was using very very tight ttls,
tons of watchers and pushing lots of data through etcd. Lets remove
this.

dalbani/fleet,octoblu/fleet,bcwaldon/fleet,wuqixuan/fleet,thepwagner/fleet,thepwagner/fleet,hhoover/fleet,improbable-io/fleet,bcwaldon/fleet,mookjp/fleet,mwhooker/fleet,mwitkow-io/fleet,giantswarm/fleet,ecnahc515/fleet,WPMedia/fleet,jonboulle/fleet,dongsupark/fleet,mischief/fleet,dongsupark/fleet,hhoover/fleet,flandr/fleet,bviswana101/fleet,mischief/fleet,mookjp/fleet,WPMedia/fleet,mwitkow/fleet,improbable-io/fleet,endocode/fleet,mwhooker/fleet,jonboulle/fleet,webwlsong/fleet,giantswarm/fleet,coreos/fleet,coreos/fleet,mwitkow-io/fleet,bviswana101/fleet,ecnahc515/fleet,endocode/fleet,dalbani/fleet,giantswarm/fleet,paveltiunov/fleet,jonboulle/fleet,flandr/fleet,mwitkow/fleet,endocode/fleet,dongsupark/fleet,octoblu/fleet,bcwaldon/fleet,esatterwhite/fleet,wuqixuan/fleet,improbable-io/fleet,ecnahc515/fleet,paveltiunov/fleet,webwlsong/fleet,dalbani/fleet,coreos/fleet,esatterwhite/fleet