Terms of service should reappear periodically/when the modal content is changed

[djriversq]

It would be great to see some more customisation to the terms of service section of LibreChat.

Mainly I'm thinking the below two features:

• Customisable acceptance period, so a user has to re-accept the terms every 90 days for example
• Updating the modal content automatically marks all users as needing to accept the terms upon their next login