Add APIs to perform syntax and content validation

Ingestion workflows perform two types of validation as it relates to schema definitions:

• Is the content syntactically correct according to the specified kind's schema definition
• Is the intent of content correct (e.g., does cited data exist)

The implementation of these validations currently exists within Python code as libraries or Airflow DAG operators. This logic is better suited as a set of API endpoints that can perform this type of validation enabling external toolsets easy access to this functionality. The types of validation that occur can be found within this guide under the How the Manifest Ingestion workflow functions section.

The validation logic for content adhering to schema definitions should exist as synchronous API endpoints.