Use URI Templates for CRUD URLS

[steve-r-west]

Let's replace all the %1 and %2 in the resources.yaml with URI Templates, that have the resource type.

e.g.

get-collection:
    docs: "https://documentation.elasticpath.com/commerce-cloud/docs/api/promotions/get-promotion-codes.html"
    url: "/v2/promotions/%1/codes"
  get-entity:
    docs: "https://documentation.elasticpath.com/commerce-cloud/docs/api/promotions/get-promotion-codes.html"
    url: "/v2/promotions/%1/codes"
  delete-entity:
    docs: "https://documentation.elasticpath.com/commerce-cloud/docs/api/promotions/delete-promotion-codes.html"
    url: "/v2/promotions/%1/codes/%2"
  create-entity:
    docs: "https://documentation.elasticpath.com/commerce-cloud/docs/api/promotions/create-promotion-codes.html"
    url: "/v2/promotions/%1/codes"

to

get-collection:
    docs: "https://documentation.elasticpath.com/commerce-cloud/docs/api/promotions/get-promotion-codes.html"
    url: "/v2/promotions/{promotions}/codes"
  get-entity:
    docs: "https://documentation.elasticpath.com/commerce-cloud/docs/api/promotions/get-promotion-codes.html"
    url: "/v2/promotions/{promotions}/codes"
  delete-entity:
    docs: "https://documentation.elasticpath.com/commerce-cloud/docs/api/promotions/delete-promotion-codes.html"
    url: "/v2/promotions/{promotions}/codes/{promotions_codes}"
  create-entity:
    docs: "https://documentation.elasticpath.com/commerce-cloud/docs/api/promotions/create-promotion-codes.html"
    url: "/v2/promotions/{promotions}/codes"

Importantly the name of the parameter MUST be one of the keys in the resource.yaml.