Refactor state transitions into workflow service

Program.cs

@@ -39,6 +39,7 @@ builder.Services.AddScoped<SuggestionWorkflowService>();
 builder.Services.AddScoped<VoteWorkflowService>();
 builder.Services.AddScoped<AdminWorkflowService>();
 builder.Services.AddScoped<ResultsWorkflowService>();
+builder.Services.AddScoped<StateWorkflowService>();
 
 builder.Services.ConfigureHttpJsonOptions(options => { options.SerializerOptions.Converters.Add(new JsonStringEnumConverter()); });