Moving Jaeger variables out of Dockerfile

[kameshsampath]

Currently the Jaeger variables are added as ENV in Docker file:

  ENV JAEGER_SERVICE_NAME=customer\
  JAEGER_ENDPOINT=http://jaeger-collector.istio-system.svc:14268/api/traces\
  JAEGER_PROPAGATION=b3\
  JAEGER_SAMPLER_TYPE=const\
  JAEGER_SAMPLER_PARAM=1

We could avoid this and add them to Kubernetes Deployment YAML

(OR)

Except for JAEGER_SERVICE_NAME other variables are pretty common for all the services, so all other variables could be added to ConfigMap and referred via configMapRef in Deployments.