refactor rules engine for key value structure with spec compliance

[bcpeinhardt]

An allow rule can have a single domain pattern, like domain=google.com.
Subdomains are automatic matches.
To require subdomains only, use domain=*.github.com.
An allow rule can have multiple method and path patterns, separated by commas, like method=GET,HEAD or path=/wibble,/wibble/*.
A trailing asterisk in a path pattern, like /wibble/*, matches any number of trailing segments.
A leading asterisk in a domain pattern, like *.github.com, matches any number of subdomains. An asterisk in the middle of a domain or path pattern matches exactly one middle segment.

I think this encourages specific concise rules around individual domains, like --allow "domain=api.github.com method=GET,HEAD path=/repos/octocat/*/issues"

P.S. I realize the line count is somewhat daunting but that is mostly tests.

[bcpeinhardt]

This file has a set of integration tests that go through the full parse and match cycle that should illuminate the edge cases of how this syntax works 😎