Rego policy support

[achamayou]

Add support for a "policyRego" field in configuration, similar to "policyScript" but allowing the definition of Rego policies executed by rego-cpp.

A sample policy may be:

package policy

default allow := false

allow if {
  input.phdr.cwt.iss == "valid_issuer"
  input.phdr.cwt.svn >= 4
}

If both a policyScript and a policyRego are defined, both must pass for the registration to complete.

All JS policy testcases have been templatised to run a rego equivalent, including performance regression test_perf, which feeds into the bencher dashboard.

[ivarprudnikov]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[achamayou]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[achamayou]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).