Deprecate Cobra

[jdknives]

Similar to viper, Cobra has quite a large number of dependecies, notably Prometheus, which itself has a lot of dependencies. We should check for another project such as

• http://github.com/urfave/cli
• http://github.com/alecthomas/kingpin
• https://github.com/spf13/pflag

[evanlinjin]

I don't think this is a good idea.

This entire package will need to be changed: https://github.com/skycoin/cx-chains/tree/master/src/cli