Add logging functions with string formatting

[farshidtz]

The current logging functions take string as input. It would be useful to add corresponding functions (Debugf, Errorf, Infof, Warnf) to accept string formats in a similar fashion to fmt.Printf.

Example code that can be simplified:
https://github.com/edgexfoundry/edgex-go/blob/3acce916edd26c48cc534c43f5f6a7ed858771e5/snap/local/hooks/cmd/configure/configure.go#L552

Moreover, the existing functions can be changed to accept one or more interfaces, instead of just one string. See fmt.Print.