support for modification to global config via user supplied sed script

[dlbewley]

The httpd image has support for developer provided sed input that can override the global config.

Can the nginx image be altered so a similar mechanism can be used to do things like enable /nginx_status with the server { } block?

[eliskasl]

@hhorak ping, do you plan to address this any time soon?

[eliskasl]

Also note that with hardcoded localhost in the default config, without the possibility to override, this is causing issues with route creation in OpenShift.