added CategoryPickerFlowStep and FirstPartComponentInitializer

[deepchoudhery]

• added CategoryPickerFlowStep

  • Each CommandInfo has a DisplayCategory property. These are going to be presented in a selection flow before the project picker.
  • Then all applicable CommandInfos are presented
  • Only applicable in the interactive mode
  • The order of steps was : StartupFlowStep --> SourceProjectFlowStep --> CommandPickerFlowStep --> CommandExecuteFlowStep
  • The order of steps is : StartupFlowStep --> CategoryPickerFlowStep --> SourceProjectFlowStep --> CommandPickerFlowStep --> CommandExecuteFlowStep

• added IDotNetToolService.InstallDotNetTool

  • install a dotnet tool globally using dotnet tool install -g

Sample gif (ignore the debugger and Redis scaffolder details)