Add HTTPS-based LoadBalancerService generator test

The load_balancer_https-output.yaml file was generated from a
live load balancer EdgeGateway, configured via the UI.

The load_balancer_https-input.yaml file was created manually to match.

Tests for this are currently failing, since there are assumptions in the
generator that are not marrying to the actual API. These will be fixed in
subsequent commits.
Re-order Interface hash for LoadBalancer

The :type parameter appears first in the hash when retrieved
from the API.

Not vital for operation, as HashDiff accounts for re-ordering of hashes,
but tests are failing due to the hash order being wrong.
Handle persistence method for LoadBalancerService

Working at least for SSL_SESSION_ID persistence method.

May require further development to support cookie based for HTTP
LoadBalancer URI is only reqd for HTTP

The LoadBalancerService HealthCheck URI is only specifiable
for HTTP services.
LoadBalancer default ports are always specified

The UI by default will create port entries for disabled and
enabled services.

Make our code mirror this behaviour.
LoadBalancer HealthCheckPort is empty by default.

As per UI-created HTTPS load balancer pool/VS, the HealthCheckPort
field is blank by default.
Remove confusing comments from test data file

These comments are largely out of date and are not useful here.