Add configurable DMI delays 

1. Add delay in ONAP DMI stubs, delay for any endpoint 
   1. org/onap/cps/ncmp/dmi/rest/stub/controller/DmiRestStubController.java has 3 rest endpoints. Separate delay parameter for each
2. application yaml spring variables (not document)

A/C

1. can set delay for each endpoint using during a docker environment variable (in ms granularity)
2. agree realistic default values by contacting csaba.eder 

Realistic delays from Csaba Eder:

• Not official measurements
• The response times on these endpoint highly depend on the number of parallel requests, the load on the system, and the nature of the request
• From deployment where some tests were run in the past days, the Prometheus metrics were ** checked
• These are the successful responses. modules and moduleResources endpoints often respond with 503 error code in the middle of model processing

1. http://\ {dmiHost}:{dmiPort}/dmi/v1/ch/{cmHandle}/modules
   ** average response time between 0.07-0.1 sec
   # http://\{dmiHost}

   :{dmiPort}/dmi/v1/ch/{cmHandle}/moduleResources

   • average response time between 0.85-1 sec
2. http://\ {dmiHost}

   :{dmiPort}/dmi/v1/data

   • In environment with 20 parallel requests the average response time is between 1.25-2.5 seconds /request.
   • Where 1.25sec response time is a quite small request with small delay, and 2.5sec  response time is a quite big request with higher delay.