Add separate token lifetime limits for administrators

This PR introduces a new configuration option--max-admin-token-lifetime that allows administrators to create API tokens with longer lifetimes than regular users. By default, administrators can create tokens with a lifetime of up to 7 days (168 hours), while the existing--max-token-lifetime setting continues to apply to regular users.

The implementation:

• Adds a newMaximumAdminTokenDuration field to the session configuration
• Modifies the token validation logic to check the user's role and apply the appropriate lifetime limit
• Updates the token configuration endpoint to return the correct maximum lifetime based on the user's role
• Adds tests to verify that administrators can create tokens with longer and shorter lifetimes
• Updates documentation and help text to reflect the new option

This change allows organizations to grant administrators extended token lifetimes while maintaining tighter security controls for regular users.

Fixes#17395