Add (experimental) API proxy to Kalamar

[Akron]

Mojolicious now provides a low cost proxy handler, that should be tested as the primary entrance for API request. This has the following advantages over Apache proxying:

• consistent client IP handling
• consistent Piwik integration
• consistent API requests (removal of current API proxies like matchinfo)
• single open port for Vagrant

[Akron]

I added a working proxy we should test before deployment. As long as /api is governed by Apache, the changes shouldn't have any effect in deployment, but we should make sure, the API exposure is no security problem. If we want to limit the proxy to certain APIs first, we should do that.

The proxy will be handled as experimental as long as the method in Mojolicious is considered experimental.