Add custom OpenAPISchemaGenerator to fix Swagger endpoint URLs

[TimJentzsch]

Relevant issue: Closes #131

Description:

This adds a custom OpenAPISchemaGenerator in order to add /api/ to all API requests on Swagger.

Checklist:

• [x] Code Quality
• [x] Pep-8
• [ ] Tests (if applicable)
• [ ] Success Criteria Met
• [x] Inline Documentation
• [ ] Wiki Documentation (if applicable)