Add the Set search

## Scryfall Documentation
https://scryfall.com/docs/api/sets

## What to do?
Theres a section for search of Magic sets. The idea is to eventually have all the functions to each category of search on the API.

- [ ] List of all sets (`/sets`)
- [ ] Get set by code (`/sets/:code`)
- [ ] Get set by Id (`/sets/:id`)
- [ ] Get set by TCGPlayer Id (`/sets/tcgplayer/:id`)

The issue is to implement set search functions for the Scryfall API. Start by examining the existing API client structure in the gem, likely in lib/scryfall/. Look for similar endpoint implementations (e.g., for cards). The Scryfall API documentation for sets (https://scryfall.com/docs/api/sets) specifies the endpoints. Implement methods for listing all sets, getting a set by code, by ID, and by TCGPlayer ID. Test by making requests to the API and ensuring the responses are correctly parsed.

Written by the indexing model from the issue text.