Refactor `clean_projects` to reduce redundancy in outputs

[tgilon]

Affected Component/Workflow

• I have labeled this feature with the affected component(s) using GitHub labels (e.g., SB, CBA, documentation, etc.).

Overview

This issue suggests refactoring the clean_projects script to reduce the redundancy in its outputs. Currently, both rules.clean_projects.output.transmission_projects and rules.clean_projects.output.methods define the transmission projects. The methods output is an extension of the transmission_projects output, providing additional information: planning_horizon and method (PINT / TOOT).

This issue is a follow-up to #802.

Scope & Key Deliverables

Refactor the scripts to produce two distinct outputs:

• transmission_projects defines the project specifications
• methods defines uses the project_id as key and defines the planning_horizon and the method

Implementation Tasks

No response