Add support for health check timeout configuration

[beyhan]

What's the user value of this feature request?
Health check configuration will be made more convenient for users not familiar with the CF APIs.

Who is the functionality for?
CF users willing to configure CF health checks via the CF CLI.

Who else is affected by the change?
This feature isn't a breaking change. It suggest to extend the current options supported by cf set-health-check.

Describe the solution you'd like
The CF V3 APIs support a timeout parameter as described in the docs. I'm suggesting to add an additional option to the cf set-health-check command which is called --timeout and can be used to configure the duration in seconds that health checks can fail before the process is restarted.

Describe alternatives you've considered
A workaround is to use the CF APIs directly to set the health check timeout. This can work like this:

cf app <my-app-name> --guid #get app guid
cf curl /v3/apps/<app-guid>/processes #list app processes information
cf curl -H "Content-Type: application/json" -X PATCH -d @health-conf.json /v3/processes/<process-from-previous-command> 

The content of health-conf.json could be something like this:

...
"health_check": {
        "type": "http",
        "data": {
          "timeout": 120,
          "invocation_timeout": null,
          "endpoint": "/health"
        }
      }
...

[gururajsh]

Hi @beyhan. Thank you for opening the issue. Will discuss this with the team and get back to you.