[Feature] - Use XDG_CONFIG_HOME to store config file

[cjones-vultr]

Is your feature request related to a problem? Please describe.
I'm always frustrated when applications litter my home directory with their custom configuration files instead of using the standard XDG_CONFIG_HOME folder to organize their config files.

Describe the solution you'd like
Ideally, the default location to look for the config file would be ${XDG_CONFIG_HOME:-$HOME/.config}/vultr-cli/config.yaml

Describe alternatives you've considered

• Manually putting the config each invocation
• Wrapping the command in a shell alias to always pass the config string

[optik-aper]

That makes sense. I'll workout how this is handled in cobra and implement it.