Fix scaffold to support rest-json style API (#1291)

* append appropriate urls when scaffolding

* make dispatch for rest-api

* fix dispatch for rest-json

* fix moto/core/response to obtain path and body parameters

* small fixes

* remove unused import

* fix get_int_param

* fix scaffold

* fix formatting of scaffold

* fix misc

* escape service to handle service w/ hyphen like iot-data

* escape service w/ hyphen

* fix regexp to extract region from url

* escape service

* fix syntax

* skip loading body to json object when request body is None

scripts/template/lib/urls.py.j2

@@ -5,5 +5,9 @@ url_bases = [
     "https?://{{ endpoint_prefix }}.(.+).amazonaws.com",
 ]
 
+{% if api_protocol == 'rest-json' %}
+response = {{ service_class }}Response()
+{% endif %}
+
 url_paths = {
 }