Implemented a DELETE request for the /api/pokemon/{id}, for deleting a specific pokemon from the data lists.

Implemented a GET handler for /api/pokemon/{id}, that returns the specified pokemon by id, if the pokemon with the ID does not exist, it responds with 404.

[WIP] Add CRUD and trainers

[WIP] Update OpenAPI

Practical session 3

Added the option to delete a selected trainer from the list, as well as made the details section update correctly after an update and deleting.

Added a trainers page to pokeApp, that displays the trainers registered in the system in a similar way to the default Pokemon page. Located on the /pokemon/trainers.html endpoint.