[Backend]Add password complexity settings

This is a sub-issue of #354963 (closed).

Proposal

To support the requirement from the parent issue, the following steps should be implemented.

• Four boolean columns should be added to application_settings table, including password_uppercase_required, password_lowercase_required, password_number_required, password_symbol_required
• The default values of these four fields should be false to keep the default behavior of password
• This configuration should only be available for Premium plan and Ultimate plan