fix: add courseapi

[DudeUnleashed]

Description

Created entities Course. This will allow access to various information relating to courses for the Courseflow component of OnTrack. Various GET, POST, PUT and DELETE endpoints created and implemented, with appropriate tests.

Type of change

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• With the API running, cd into doubtfire-api
• Run the following command: bundle exec rails test test/api/courseflow/course_api_test.rb
• Can manually test endpoints using postman.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation if appropriate
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have created or extended unit tests to address my new additions
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[sammyrolfe]

All tests run successfully, all endpoints tested successfully.

[aNebula]

How come there's a mixture of utf8mb3_unicode_ci and utf8mb4_general_ci ?

[DudeUnleashed]

Originally there were uft8 as the charset, sql then changed the old entries to uft8mb3, this was as it is outdated and they wish to use the uft8 shorthand elsewhere for their new versions. Any new table generated now uses the uft8mb4 charset

[aNebula]

All tests run successfully, all endpoints tested successfully.

@sammyrolfe - this PR has been updated and merge conflict resolved - can you please review this one more time?

[aNebula]

@DudeUnleashed are these already included in the PRs that came next? Otherwise please open upstream PR against https://github.com/doubtfire-lms/doubtfire-api/tree/new/course-flow.