Optional country query param for /Employees/{alias}

[mathiazom]

Closes #132

Makes the country query param optional for /Employees/{alias}, similar to the /Employees endpoint.

with query param

without query param

with non-matching query param

[mathiazom]

Is there a reason for requiring the country parameter? Are the email aliases only unique within each country?

[mathiazom]

Let's leave this as required, since we don't have an explicit requirement that aliases should be unique across countries.