changes in calculation for GR values - cover a common case

[MarcHafner]

Description

What changed?

Related JIRA issue: https://jira.gene.com/jira/projects/GDR/issues/GDR-2155

Why was it changed?

I found that the matching of the control by Barcode (or other nested nested_keys) is too stringent. In case there is a value for another plate, we should backfill it. This is important as Day0 plate will have another barcode by design but they are meant to be used for normalization.

Checklist for sustainable code base

• [ ] I added tests for any code changed/added
• [ ] I added documentation for any code changed/added
• [ ] I made sure naming of any new functions is self-explanatory and consistent

Logistic checklist

• [ ] Package version bumped
• [ ] Changelog updated

Screenshots (optional)

[MarcHafner]

@bczech : can you review my edit and merge with master? thanks