Management API endpoint for Nuxeo properties

Access to the configuration.properties to check what are the actual values templated and used by Nuxeo can be very tricky:

• in a scalable environment where nodes can be replaced any time
• in a container world where getting "in" Nuxeo is nearly impossible or at least not recommended.

One way to mitigate this issue, having an additional endpoint within the management API to export all nuxeo properties (nxserver/config/configuration.properties).

The REST response will contain both configured properties (the ones from the configuration.properties file) and the runtime properties (the ones from Framework#getProperties). The format could be:

{
  "configuredProperties": {
    "NUXEO_HOME": "...",
    ...
  }
  "runtimeProperties": {
    "NUXEO_HOME": "...",
    ...
  }
}

In order to keep properties safe, we will use the code from MaskSensitiveData class before writing data to the response.