Add unit tests for remote dev module in agentk

What does this MR do

This MR introduces the following changes

• Merged workspace parser into the informer logic for easier testing
• Moved some constants into a dedicated model package (to avoid cyclic dependency issues)
• Adds a unit test to capture the complete flow for workspace termination
• Modifies the existing unit test for workspace creation. Modifications include testing across multiple cycles of worker runs(earlier test covered 1). Additionally, code has been refactored a bit to make use of helpers introduced
• Fix a potential memory leak issue