[REQ][csharp-netcore] Add Request Options as a parameter to the Wrapper API methods

Created by: RubberChickenParadise

Is your feature request related to a problem? Please describe.

In the Typescript-axios generated client, all the methods take a RequestOptions object to enable callers a bit more control over resulting request. This is useful in several scenarios where there may need to be additional headers added only one place in the code.

Describe the solution you'd like

There is already the Request Options object that is being instantiated in each method. Add the RequestOptions as a method parameter and add a guard if statement to initialize the RequestOptions if it is the default instead of always initializing RequestOptions as a new instance.

Describe alternatives you've considered

Custom mustache file.

Additional context

Adding this to the default generated files will bring the c# net core API more inline with other language client generators.