Support operation links in OpenAPI3 generator

[markcowl]

This is to support paging and lro scenarios in OpenAPI 3.

• move OperationLink decorator into the core or core http library
• When emitting an operation in OpenAPI3, use the OperationLink accessor to get operation link details and transform into OpenAPI3.
• emit the link name and description (corresponding to the name passed to '@operationLink')
• The parameter / property maps in operation link decorators will need o be translated to request and response properties per openAPI3 rules when emitting link decorators:
  • RequestParameter<"paramName"> -> $request.<location-specifier><paramName>
  • ResponseProperty<"propertyName"> -> $response.<location-specifier><propertyName>
  • location specifiers include:
    • @header -> header.
    • @path -> path.
    • @query -> query.
    • body property -> .body/#

[markcowl]

estimate: 8