Create Basic CRUD Routes for Transaction

Create routes for Transaction that allow for the following:

- Create:
- Location → "shearly-next/app/api/transaction/create/route.ts".
- Method → POST
- Goal → Given a body with dateTime, appointmentId, clientId, discount, subtotal, tax, total do the following:
- Verifies if if contains a proper dateTime.
- Verifies if a client with clientId exists.
- Verifies if an appointment with appointmentId exists.
- Finally, if everything is correct, create the transaction.

- Find All:
- Location → "shearly-next/app/api/transaction/find/route.ts".
- Method → GET
- Goal → Must be able to get all Transactions from database.

- Find By Id:
- Location → "shearly-next/app/api/transaction/find/[id]/route.ts".
- Method → GET
- Goal → Must be able to get a single Transaction by ID.

- Edit:
- Location → "shearly-next/app/api/transaction/edit/[id]/route.ts"
- Method → PUT
- Goal → Must allow to edit any property of a Transaction except Client and Appointment.

- Delete:
- Location → "shearly-next/app/api/transaction/delete/[id]/route.ts"
- Method → DELETE
- Goal → Must be able to delete a Transaction given an id.