Custom Status Code for non-loaded modules

MERGE REQUEST

MR Guidelines

Overview

This MR changes the http status code returned when a module is not available from 404 to 490 to provide a clear distinction between a module not being loaded and a resource not being available. e.g. when downloading a skyline it's not clear if 404 means that the sky file wasn't found or if the module isn't available.

Checklist

Review and complete the checklist to ensure that the MR is complete before assigned to an approver.

• All new methods or updated methods have clear docstrings
• Testing added or updated for new methods
• Any new packages are added to Makefile and .gitlab-ci.yml
• API documentation updated for API updates
• Module README.md updated for changes to workflow
• Issue added to Sia-UI repo for new supporting features
• Changelog File Created