CLI setup command should support visualstudio.com domains

[bnookala]

As a:

spk setup user

I want:

spk setup to support my organization hosted on visualstudio.com ie org.visualstudio.com

So that:

I can use my organization hosted on visualstudio.com to run spk setup

Describe the solution you'd like:

spk setup should prompt for where my devops organization exists, and confirm that it exists

Acceptance Criteria:

• spk setup should prompt which domain (dev.azure.com or visualstudio.com to use
• spk setup should confirm if organization hosted on the selected domain exists

Additional context:

Historically, visualstudio.com was where azure devops hosted organizations - dev.azure.com is the new domain

Does this require updates to documentation?:

yes

[andrebriggs]

Related to #1201

[andrebriggs]

@bnookala I think we should close this or turn it into a feature where we tell the user that we don't support *.visualstudio.com. See here for more reference.

Thoughts?

cc @dennisseah