Allocate random port for internal components

[lukidzi]

What happened?

When running more than one kuma-dp on a VM, users may encounter port conflicts. The Admin API uses port 9901, and the application probe uses port 9902. In such cases, users need to explicitly configure the ports for the next kuma-dp to avoid conflicts. We could implement a check to validate if the port is already in use, allocate a random available port, and log a message such as: application probe is exposed on port: xxxx.

[jijiechen]

This applies to these components:

• Application probe proxy (defaults to 9001)
• Envoy readiness reporter (defaults to 9902)

[jijiechen]

If we randomize these ports, it may potentially be conflict with application ports.

[jakubdyszkiewicz]

Triage: Random ports can cause bugs. Consider implementing this kumahq/kuma-website#1786 or kumahq/kuma-website#2024