Supported Envoy v2 API

Prominent changes from v1 based demo app are:

• Changed general port for front proxy from 80 to 8000
• Changed docker compose version from 2 to 3.7 (seeCompose file version 3 reference)
• HTTP Connection Manager API Change:
  • v1 API: envoy.http_connection_manager in v1 API
  • v2 API:envoy.filters.network.http_connection_manager
• Tracking config for both Jaeger and Zipkin
  • endpoint: /api/v1/spans to /api/v2/spans
• Stopped usingenvoy.api.v2.route.RouteMatch.regex, deprecated option