Update orca-mock API with CORS headers

[k-jano]

After changes with using orca-mock API in orca-ui, to use application in every browser CORS headers need to be present on requested source.

Here is an example error message:

Access to XMLHttpRequest at 'http://localhost:5000/v1/graph' from origin 'http://localhost:3000' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Now in development process browser with disabled web security option can be used. In case of Google Chrome:
google-chrome --disable-web-security --user-data-dir="/tmp/chrome-test"

[filwie]

It would be nice to add reverse proxy in front of our services so that we can have the same origin. The API could be in a subpath /api. I will try to update docker-compose with additional container soon.