Add APM for API-Builder4Elastic

[cwiechmann]

Is your feature request related to a problem? Please describe.
To get more visibility about the entire solution, the API-Builder4Elastic should report application performance monitoring (APM) to Elasticsearch.
With that, customers can identify potential problems in API-Builder much easier than using the Log-File.

Describe the solution you'd like
The solution is going to use the standard APM Agents for Node.js from Elastic: https://www.elastic.co/guide/en/apm/agent/nodejs/current/index.html
It will be integrated into the app.js right at the top:

const apm = require('elastic-apm-node').start({
	serviceName: 'APIBuilder4Elastic',
	serverUrl: 'http://my-apm-service:8200'
})

• It should be configurable for the customer if he wants to collects API-Builder APM information
  • default is enabled
  • It should be enabled when a serverUrl for the APM is given
• customers should have the choice, if an APM-Service should be deployed along with Elasticsearch
  • or they can use an existing APM service
• the service name defaults to the API-Builder application name: apibuilder4elastic as it configured in the package.json
  • customer can overwrite this. For instance to support multiple environments (Prod, QA, ...)