feat: Adding createReservations function to the EnvoyUserAPI

[ArvindEnvoy]

This function will let users create reservations. There is a new function called createReservation and the associated types to facilitate interaction with the Spaces endpoint that creates the reservation.

New reservation functionalities:

• src/resources/ReservationResource.ts: Added new interfaces ReservationAttributes, ReservationCreationAttributes, and ReservationModel to define the structure of reservation data.
• src/sdk/EnvoyUserAPI.ts: Imported ReservationCreationAttributes and ReservationModel from ReservationResource and added a new method createReservation to handle the creation of reservations. [1] [2]

Package version update:

• package.json: Updated the package version from 2.2.1 to 2.2.3.