Migrate GET routes

[rikedyp]

• All GET routes registered and responding correctly
  • Review current tests
  • Add tests if API changes
• OpenAPI schemas attached to each route
• Old Get.aplf dispatch file deleted
• Existing functionality preserved (search, pagination, filtering, recommendations)

[rikedyp]

Some tests require the error handling mechanism to be in place. Will only get as far as major route migration and passing tests that do not require error handling behaviour. Tests related to errors will be handled in #118