Add policy support for services

The policy framework should incorporate services.

**Examples**
Throw policy violation if:
* A service contains or matches a specified URI string
* A service matches a specified scheme, host, port, etc
* A service crosses a trust boundary
* Access to a service (does/does not) require authentication
* A service has either an inbound or outbound flow of data
* A service has an inbound or outbound flow and the data involved matches a specified data classification

This enhancement is built upon the work that will be implemented in #843 .