cli auth scope for vault secrets

[tongueroo]

Closes #7

Some notes for posterity:

• Only took a quick look at this based on Support CLI Auth Scoping #7
• It looks like the other auth provider strategies support a "resource/scope" already.

• armrest/lib/armrest/api/auth/login.rb

  Line 13 in af56b66

  resource: resource,

• armrest/lib/armrest/api/auth/metadata.rb

  Line 30 in af56b66

  params = { resource: resource }

• The resource method comes from

  armrest/lib/armrest/api/settings.rb

  Line 17 in af56b66

  def resource

• So was able to use the resource method in the CLI auth provider strategy also.
• It looks like the terraspace_plugin_azurerm really only has a helper for the azure_secret right now. So just accounting for the --scope https://vault.azure.net/.default for now.
• Unsure what the general --scope option would be for others. If others know what they are, let me know or others know so the code can be more generalized.

[tongueroo]

Released in 0.2.2

[syepes]

Great, thanks for the rapid fix!