Endpoint for validating a dataset against a schema

Description

An endpoint that accepts a file and the name of a schema in the database, and validates the schema.

[x] Create a POST endpoint that accepts a file to be validated and a string, which will be the name of a schema to validate against
[x] Create a service that retrieves that schema with the given name
[x] Create a service that performs the validation
[x] If the schema is valid, return 202 NO CONTENT status, else return 400 BAD REQUEST with a json object explaining what is wrong is possible