editable description

[``* `#16988` editable description``](http://community.openproject.org/work_packages/16988)
I would rather move this in a more general method ``render(text, context)`` with something like the following body:
```JS
function render(text, context) {
  return $http({
    url: PathHelper.apiV3TextilePath(context), // see comment above for details
    ...
}
```