[WIP] Add reusable Fortify on Demand SAST analysis workflow

[Copilot]

Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

Original prompt

Create a reusable Fortify on Demand SAST analysis workflow based on the attached fortify-analysis.yml, for use by parser plugin repositories. The workflow should:

• Be added to the fortify/.github repository under .github/workflows/fortify-analysis.yml
• Use a workflow_call trigger for consumption by other repositories
• Include all relevant job(s) and environment configuration as in the original, except for repository-specific logic
• Reference secrets as inherited from the caller repo
• Reference and update documentation/comments appropriately for use as a reusable workflow

This pull request was created as a result of the following prompt from Copilot chat.

Create a reusable Fortify on Demand SAST analysis workflow based on the attached fortify-analysis.yml, for use by parser plugin repositories. The workflow should:

• Be added to the fortify/.github repository under .github/workflows/fortify-analysis.yml
• Use a workflow_call trigger for consumption by other repositories
• Include all relevant job(s) and environment configuration as in the original, except for repository-specific logic
• Reference secrets as inherited from the caller repo
• Reference and update documentation/comments appropriately for use as a reusable workflow

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