feat(router): customize health-check route and add SSL redirect

I pulled #2781 and #2782 into the same PR so they'd be easier to test. This also enabled me to refactor the default route for both the healthcheck endpoint and SSL redirect into the same config block, cleaning up the config and ensuring they apply to everything (i.e. before the controller, builder, store-gateway, or app routes are processed). 

TESTING: add an SSL cert, enable SSL redirects, change the custom health-check endpoint, and ensure nothing is broken
I guess the question is whether we want `/health-check` to respond to all requests, including app requests. I could see it being useful for controller requests and not just when there's no matching host (i.e. `default_server`). 

If we don't have it for apps, there's really no need to ever rename the health-check endpoint.

Locally I've refactored this into:
```
    server {
        listen 80;
        {{ $healthEndpoint := or .deis_router_healthEndpoint "/health-check" }}
        location {{ $healthEndpoint }} {
            default_type 'text/plain';
            access_log off;
            return 200;
        }
        {{ $useSSLRedirect := or .deis_router_redirectAllHTTPToHTTPS "false" }}
        {{ if eq $useSSLRedirect "true" }}
        location / {
            return 301 https://$http_host$request_uri;
        }
        {{ end }}
    }
```