Validation Manager

# :rocket:

- [ ] Is your feature request essential for your project?

### Describe the workflow you want to enable
Encapsulate the existing validation and cleaning of external data resources into a single library and CLI. The result of this project will be a single CLI tool that we can use to validate external resources, either manually or by integrating into an orchestration/workflow system such as Apache Airflow.

### Describe your proposed implementation
- Write a command-line tool that verifies previously downloaded external data resources
- The tool ensures that the data is correct (format, data types, value domains, missing values, etc.), and either cleans the input data or responds with an error
- The tool should be well documented with a focus on code quality

### Describe alternatives you've considered, if relevant
Suggestions welcome!

### Additional context
This issue is part of a list of ideas for new contributors.

- **Requirement:** Python
- **Level:** Easy
- **Mentor:** @ToddG, @jon-hagg, @rouille

Start by locating the existing validation and cleaning logic for external data resources, then review how the project currently generates or consumes those resources. Define the CLI and its workflow-system integration around the stated checks for format, data types, value domains, and missing values. Done means the behavior is documented and the tool can validate, clean, or report errors for downloaded resources.

Written by the indexing model from the issue text.