What would you like to be added:

This issue is for managing the process of adopting plugin architecture to piped. The ideal result is to make all platform providers' logic independent from the piped core logic (the controller package).

Tasks pool break down 💪

• Revise the plugin planner interface <- @khanhtc1202 @Warashi
• Implement piped plugin grpc service <- @khanhtc1202
• Implement piped plugin grpc secret decryption endpoint <- @khanhtc1202
• Implement piped planner which calls to the plugin deployment service <- @khanhtc1202
• Implement k8s plugin: PlannerService interface implementation <- @Warashi
• Update model.PipelineStage model:
  • mark Predefined and Visible as deprecated
  • add rollback field
  • add timeout field

Why is this needed: