update server.yml to add dynamic port support

[stevehu]

Default is false as this is only needed when deployed to Kubernetes cluster. You can use it on a single server deployment with docker-compose or java -jar as well along with Consul registry and discovery.

When using dynamic port, service registry and discovery are required.

The following is the default section added to the server.yml

# Dynamic port is used in situation that multiple services will be deployed on the same host and normally
# you will have enableRegistry set to true so that other services can find the dynamic port service. When
# deployed to Kubernetes cluster, the Pod must be annotated as hostNetwork: true
dynamicPort: false

# Minimum port range. This define a range for the dynamic allocated ports so that it is easier to setup
# firewall rule to enable this range. Default 2400 to 2500 block has 100 port numbers and should be
# enough for most cases unless you are using a big bare metal box as Kubernetes node that can run 1000s pods
minPort: 2400

# Maximum port rang. The range can be customized to adopt your network security policy and can be increased or
# reduced to ease firewall rules.
maxPort: 2500