VCD login shouldn't be required for running emulated environment

[jmoroski]

Description
If I want to create a simple proof of concept plugin using vcd-ext new and then test it in a local sandbox via the vcd-ext serve command, I shouldn't need to first log into a real VCD instance.

One of the selling points of the local emulated environment is that it provides an alternative to a live environment for tighter feedback loops and general sandboxing of plugins without provider credentials

To Reproduce
Steps to reproduce the behavior:

1. Install the latest vcd-ext
2. Run vcd-ext new demo
3. Run 'vcd-ext serve`
4. See error

~/code/Demo$ vcd-ext serve
    Error: Config file missing at /home/jmoroski/.vcd/config. Try logging in first.

Expected behavior
A running emulated environment