Add Support for Composite Actions

[aweris]

Description

gale currently does not support composite actions. Composite actions allow users to bundle multiple steps into a single action. To improve gale compatibility with a broader spectrum of Github Actions, it's crucial to implement support for composite actions.

Current behavior:

• gale cannot recognize or execute composite actions

Desired behavior:

• gale should be adept at identifying composite actions, parsing their steps, and sequentially executing them.

Tasks

• Research how Github actions setup, execute, and logs composite actions
• Update step action struct to recognise composite actions.
• Add new composite executor implements Executor interface to combine existing step execution logic with composite actions
• Ensure robust error handling and logging mechanisms for each composite action step.
• Update ci/workflows with example workflow
• Update demo directory post release of the feature with a demo with composite action