[BACK] Add pending and accepted status of invited users

[lineconquista]

❗️ Check the label before starting task, it depends on this ❗️

Currently, when someone invite another user to squad we send an invitation email, after clicking it ll be part of team. But we dont have an expiration time, token management for this invitation or status at database like "accepted" and "pending".

TO DO

• Add expiration time at JWT
• Add new role at JWT
• Add token as enabled at users-tokens
• After user clicks on invitation link, update enabled field as false since token would already been used and update status field with "accepted" value
• Add new status column at squads-users table, default is "pending"
• Add status field at list squad endpoint