Function to create and configure koa server.
Expects optional parameters:
log
- logging functionssl
- ssl configuration (value or promise resolving in ssl configuration - usually object withkey
andcert
keys)allowUnsecure
- if server is allowed to serve content over HTTP connection instead of redirecting to HTTPS
See https://github.com/salsita/nodejs-training/blob/master/src/index.js repo for usage.