This has the biggest impact on enterprise test cases that use namespaced
registrations, which prior to this change sometimes failed the initial
registration because the namespace was not yet created.
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).