Add ability to customize guard responses by moudule

[jclausen]

If a module implements cbguard, the module should have the ability to customize the responses for authorization failures, when within the modules routing namespace.

Allow for nested cbguard settings within each module's settings.

Example:

settings = {
            "cbguard" : {
                "authenticationService"           = "SecurityService@myModule",
                "authenticationOverrideEvent"     = "myModule:Main.onAuthenticationFailure",
                "authenticationAjaxOverrideEvent" = "myModule:api.v1.BaseAPIHandler.onAuthenticationFailure",
                "authorizationOverrideEvent"      = "myModule:Main.onAuthorizationFailure",
                "authorizationAjaxOverrideEvent"  = "myModule:api.v1.BaseAPIHandler.onAuthorizationFailure"
            }
}

If a customized module setting is not detected, then the top-level module settings would apply.

[elpete]

Added in 3.0.0