kontena/lb should sort overlapping KONTENA_LB_VIRTUAL_PATH services to forward requests to the most specific route

[SpComb]

If you have a default service with KONTENA_LB_VIRTUAL_PATH=/, and another service service with KONTENA_LB_VIRTUAL_PATH=/foo, the LB may forward requests for /foo/... to the default service, not the server service.

As an example, this kind of generated config will not route any requests to the healthcheck-test-500-server backend service:

   acl host_healthcheck-test-500-default_virtual_path url_beg /
   acl host_healthcheck-test-500-server_virtual_path url_beg /healthcheck-test-500
   use_backend healthcheck-test-500-default if host_healthcheck-test-500-default_virtual_path
   use_backend healthcheck-test-500-server if host_healthcheck-test-500-server_virtual_path

The routing of requests for /foo depends on the order of the generated configs... I'm not sure if this is currently even deterministic?