fix: make SARIF repository URL configurable

[kavin553]

Description

This PR removes hardcoded SARIF metadata URLs by making them configurable through application settings.

Changes made

• Added repository_url configuration to Settings.
• Added sarif_schema_url configuration to Settings.
• Updated generate_sarif_report() to use configurable values instead of hardcoded URLs.
• Added corresponding environment variables to .env.example for easier deployment and customization.

Related Issues

Closes #ISSUE_NUMBER

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

How Has This Been Tested?

• Verified the application starts successfully after adding the new configuration options.
• Generated a SARIF report and confirmed that informationUri and $schema are populated using configuration values.
• Confirmed existing functionality remains unchanged when default configuration values are used.

Checklist

• My code follows the code style of this project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.