[TASK] Configure Operate's management port to check readiness

[romansmirnov]

Related to:

With https://github.com/camunda/zeebe/issues/17062, Operate and Zeebe share the same Spring configuration. This means now Operate also opens a management port on 9600.

Overview:

Ensure that the management port is used to check Operate's liveness (like readiness, ...).

Actions:

• [ ] Configure managementPort in deployment.yml
• [ ] Use managementPort in readinessProbe, startupProbe, and livenessProbe
• [ ] Configure the context-path accordingly
• [ ] Adjust service.yml configuration to map managementPort
• [ ] Adjust Operate's service-monitor.yml settings
• [ ] Provide option to configure management port (default 9600)

[aabouzaid]

@romansmirnov Thanks for open this task :raised_hands: What is the target version for this change? will it be part of 8.5.x or it's for 8.6?