perf: process experiments in parallel

[melotic]

Refactors the ExperimentDiff to be immutable, so we can safely process the experiments in parallel. 🦀

The two processors at the moment, one to write to disk, and a future one to upload to Azure Blob Storage for internal customers, should run in parallel to not slow down CD.

[github-actions]

👋 Hi! It looks like you modified some files in the Detectors folder.
You may need to bump the detector versions if any of the following scenarios apply:

• The detector detects more or fewer components than before
• The detector generates different parent/child graph relationships than before
• The detector generates different devDependencies values than before

If none of the above scenarios apply, feel free to ignore this comment 🙂