AIP-81 Central API Communication Mechanism for CLI and Connection Command Integration

[bugraoz93]

closes: #42561 and discarding dynamic generation of requests: #42562

Summary
This PR introduces a central API communication mechanism for the CLI and adopts one of the broadest endpoint ranges in the API, focusing on connection commands. After several iterations to automate API call generation and handle edge cases, I couldn't achieve a fully dynamic request generation process. Instead, I landed on a structure similar to TaskSDK <-> ExecutionAPI. This approach simplifies reviews, maintains consistency across clients, and opens the door for better automation in future iterations, possibly in 3.1 or 3.2.

Implementation Details

• Added a central API communication mechanism for the CLI.
• Integrated connection_command.py with unit tests.
• Implemented most of the necessary CLI operations.
• Data model generation from RestAPI to CLI is handled using uv.
• Added decorators to cascade generic processes to operations.
• Created a testing framework for CLI testing, with an example implementation for connection command.
• Pending Work
• Some minor features related to the connection command are still in progress and will be added in follow-up updates before 3.0.

Note: There are two missing functionalities in this PR for the connection command. Those will be included with follow-up tasks.

• AIP-81 Implement Create Default Connections in REST API (FastAPI) #45302 (Create Default Connections)
• AIP-81 Include Overwrite Functionality to Bulk Insert API Endpoints for Connection&Pool #45303 (Overwrite the Bulk Insert Connections when Flag is passed)

Notes on task_command
While working on this, I realized that task_command behaves more like a local_command than a remote_command. This needs further discussion, especially regarding its integration with TaskSDK. From the CLI perspective, depending on TaskSDK seems cleaner than directly calling ExecutionAPI, it avoids duplication and keeps the structure consistent. Even if the CLI calls TaskSDK, the two-hop process to reach the ExecutionAPI feels a bit redundant. What do you think, @ashb (to all, please jump into discussion, I tagged Ash to follow up the previous discussion started on this in Slack)?

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[jscheffl]

Note: As PR #45312 has been merged, the code formatting rules have changed for new UI. Please rebase and re-run pre-commit checks to ensure that formatting in folder airflow/ui is adjusted.