Extract list_volumes and get_volume into pool.py

[MintCat98]

Motivation  

Currently, list_volumes and get_volume are located in context.py, but to improve modularity and maintainability, they should be moved to a separate storage/volumes/pool.py file.

Required Features

Move list_volumes and get_volume to pool.py in /storage/volumes/.

Impact  

• Code Structure Improvement:

  • Increases cohesion by isolating volume management logic from context.py.

• Enhanced Maintainability:

  • Easier to manage and modify volume-related logic independently.

• Better Extensibility:

  • Future volume-related functionalities can be managed systematically within pool.py.

• No Functional Change:

  • API behavior remains the same, ensuring no impact on external users.

Testing Scenarios  

• Verify that list_volumes returns the same data as before.

• Ensure get_volume correctly retrieves volume instances.