Create the Delete service method.

[jerry-enebeli]

Create the Delete service method. Should be able to delete all services using the(--all flag) and also be able to delete a single service using the service name.

//Commands format

//Delete all services command
gateway service delete --all

//Delete single service command
gateway service delete [service name]

//Resources
//Bolt for db
https://github.com/etcd-io/bbolt#using-buckets

//Cli Tool
https://github.com/spf13/cobra