Federated Validation Aggregation Functionality

[micdavis]

Is your feature request related to a problem? Please describe.
Currently, the only form of validation available is centralized/traditional validation on the server. (i.e. the server has a validation dataset that it runs against models to create validation reports.)

Describe the outcome you'd like:
I would like for user to have the configuration option to enable federated validation using the following steps:

1. Client pulls most recent model aggregates
2. Client runs validation on model
3. Client pushes validation results
4. Server aggregates validation results from clients

Additional context:
N/A