Add method-based binding API for validation effect

[TysonMN]

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There would be one overload for each type of validate function currently supported. All such function take 'model as input and return one of these:

1. string list
2. string voption
3. string option
4. Result<'ignored, string>

[TysonMN]

Except, don't work on this yet, but this work might depend on #424 and transitively on #362.