Create API versioning with Swagger support

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Need Swagger versioning to support Kanban v2

Sample: https://github.com/domaindrivendev/Swashbuckle.AspNetCore/blob/master/test/WebSites/MultipleVersions/Startup.cs

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See this discussion: https://github.com/Microsoft/aspnet-api-versioning/issues/60

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Solution:

1. Define the available versions

   c.SwaggerDoc("v1", new Info { Title = "Arda.Kanban", Version = "v1" });
   c.SwaggerDoc("v2", new Info { Title = "Arda.Kanban v2 (Workspaces)", Version = "v2" });

2. Define a function to classify the API in version

   c.DocInclusionPredicate((docName, apiDesc) =>
   {
   switch (docName)
   {
       case "v1":
           return apiDesc.RelativePath.StartsWith("api/");
       case "v2":
           return apiDesc.RelativePath.StartsWith("v2/");
   }
   
   // unknown version?
   return true;
   });

3. Update the Swagger UI

   app.UseSwaggerUi(c =>
   {
   c.SwaggerEndpoint("/swagger/v1/swagger.json", "Arda.Kanban v1");
   c.SwaggerEndpoint("/swagger/v2/swagger.json", "Arda.Kanban v2 (Workspaces)");
   });

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Done