Form for validating a dataset against a schema

[dcl10]

Description

Create a form which the user selects an available schema and uploads a file to validate against that schema.

Tasks

• [x] Retrieve available schemas to add to a select box
• [x] Add endpoint to backend for getting available schemas
• [ ] Submit for file to the backend
• [x] Show if the file is valid under the selected schema

[kuraisle]

Task 2 (Add endpoint to backend for getting available schemas) is covered in the /schemas endpoint if you leave the request body empty - I think