Allow support for bringing your own scan_results_bucket from home

If we allow users to specify where their results should be sent, this can allow for a central bucket that contains all scan results for all code on a given project.

Feature request from @raduraul

No file, test, or entry point is named in the issue. Start by locating the existing scan_results_bucket configuration and its result-upload path; done means users can provide their own destination and all scan results for a project can be collected in that bucket.

Written by the indexing model from the issue text.