support for escaped query parameter names in ruby

[baywet]

more details at #1445

Some query parameter names are escaped in the generated code because the are invalid symbol names in the target language (e.g. $select).

While this solves any compilation issues, it breaks the URL templating mechanism for escaped names (because the expected parameter name by the template engine will be %24select.
The ruby generation needs a way to carry that information so the template parameter matches the property name.

In other languages we've used annotations/attribute where the property is augmented by a custom attribute with the right property name the engine expects, and the add parameters method reads in that attribute if present instead of taking the property name.

Related to #1651