fix(secrets): add function to add the custom policies to the metadata integration not in the multiprocess

[lirshindalman]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Description

separate the lode detectors function from the CustomRegexDetector class and add a function to the runner to add custom detectors to metadata integration

Fix

added function to add the custom policies to the metadata_integration, not in multiprocess

Checklist:

• My code follows the style guidelines 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
• I have added tests that prove my feature, policy, or fix is effective and works
• New and existing tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules