tidy: Reorganisation of PCA Handler

[KSkwarczynski]

Pull request description

Simply move as much as possible stuff from Covariance to PCA Handler to make code easier to follow.

Changes or fixes

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Memory and CPU Usage Summary

### Memory and CPU Usage Summary

| Metric  |     Mean    |      Max    |
|---------|-------------|-------------|
| **RAM** |   314.67 MB |   315.88 MB |
| **CPU** |    96.02 %  |    97.75 %  |

Memory Usage Plot

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You can view the memory usage plot directly in the job summary from the link above.