The key thing here is to use `curl --no-keepalive` so that envoy
pre-1.15 tests will reliably use the latest listener every time.
Extra:
- Switched away from editing line-item intentions the legacy way.
- Removed some teardown scripts, as we don't share anything between cases anyway
- Removed unnecessary use of `run` in some places.
Extend Consul’s intentions model to allow for request-based access control enforcement for HTTP-like protocols in addition to the existing connection-based enforcement for unspecified protocols (e.g. tcp).