chore(validator): support validation config to map actual and predicted

[sthaha]

This PR introduces the following changes to validator

• Use predicted instead of expected terminology to align with MAPE and MSE teminology
• Add ability map actual and predicted in validations. This allwos for

config:
  mapping:
     actual: metal
     predicted: vm

validations:
  - metal: <metal-query>
    vm: <vm-query>

• Generated reports and artifacts now make use of these label
• Add support for Units

[github-actions]

🤖 SeineSailor

Here is a concise summary of the pull request changes:

Summary: This pull request refactors the validator module, introducing changes to the ValidationResult class and related functions. Key modifications include:

• Renaming expected to predicted to align with MAPE and MSE terminology
• Adding new attributes for actual_label, predicted_label, and units to support mapping actual and predicted values in validations
• Updating test functions for MSE to use predicted instead of expected
• Increasing the maximum series length for MSE tests to 1000

Impact: These changes affect the internal structure and behavior of the validator module, but do not impact the external interface or functionality, as long as users update their code to use the new attribute names.

Observations:

• The changes seem to be focused on improving the internal implementation of the validator module, which is a good practice for maintainability and scalability.
• The updated terminology and added features will likely improve the accuracy and usefulness of validation results.
• It would be beneficial to include documentation updates to reflect the changes, ensuring that users are aware of the new attribute names and their usage.

Overall, this pull request appears to be a well-structured and thoughtful refactoring effort, with a focus on improving the internal implementation and functionality of the validator module.

[KaiyiLiu1234]

lgtm