Make webpage test URL configurable

[redonkulus]

At my company, we have an internal instance of webpacktest to test internal URLs. Would be nice to make this configurable in the tool:

https://github.com/perflint/perflint/blob/master/lib/service/webpagetest.js#L114

[matthojo]

Great idea. I'll see if I can get this into the next release, shouldn't be too difficult.

[matthojo]

Started work on this with 578bd1d.

Remaining work;

• Tests still need adding
• Validate it works with real custom WPT servers
• Allow server to be set with environment variable - eaa5ade

[matthojo]

This is now available on v0.0.3.
Documentation: https://perflint.readme.io/v0.0.3/docs/command-line-interface#-s-server-string

I'll close once tests and there is validation of it working with hosted WPT servers.