Handling for routes with parameters in the url with slashes

This is a continuation of the issue resolved here:
https://issues.civicrm.org/jira/browse/CRM-1983

Drupal does not allow the passing of parameters to routes that contain slashses, since 8.0-beta13

This was discovered making the CiviCRM menu work with Drupal 8.2.5

so to get the menu you have something like this in the path:
civicrm/ajax/menujs/202/en_US/1/NFmjWSlO
with this bit: 202/en_US/1/NFmjWSlO
being parameters passed to the route as url path components
or as Drupal sees it it is either its own distinct path, which will result in a 404,
OR
its one parameter, "containing slashes"

To make it work, we had to create a PathProcessor service, and if the path is the menu path, take the parameters, replace '/' with ':' and pass those as the $extra parameter to the controller

We need to all other paths that need this handling, or figure a way to automate the path processor that is not on a path by path basis