Add CORS support to the istio based API gateway

[berndtj]

Feature Request

Detailed Description

The API gateway should be configurable to allow CORS support on endpoints. This should be supported by the istio virtualservice which is used to define the route.

Context

Possible Implementation

Complexity

• [ ] Low - Simple enhancement or bug fix, no architectural changes or refactoring
• [ ] Medium - Change requires some thought, but is relatively isolated
• [ ] High - Significant architectural change or large refactor