InitConfig finds and merges CLI configurations in the following order: system dir, home dir, current dir, ENV vars, command-line arguments https://dev.to/techschoolguru/load-config-from-file-environment-variables-in-golang-with-viper-2j2d https://medium.com/@bnprashanth256/reading-configuration-files-and-environment-variables-in-go-golang-c2607f912b63.