create use cases for auth

src/modules/auth/auth.service.ts

@@ -1,5 +1,5 @@
-import { Injectable, UnauthorizedException } from '@nestjs/common'
-import { addDays, isBefore } from 'date-fns'
+import { Injectable } from '@nestjs/common'
+import { addDays } from 'date-fns'
 import * as jwt from 'jsonwebtoken'
 import * as bcrypt from 'bcrypt'
 import { UsersRepository } from '../users/infrastructure/users.repository'