Update IP Allow List to Support Range

As-is, the IP allow list enables you to add a single computer (IP address) which works great. However, it doesn't allow you to add an IP range. IP ranges would be useful for certain corporate and VPN environments where the external IP address may be assigned dynamically, but within a known range (e.g., `123.123.0.0/24`).

The front-end implementation would require validating the `123.123.123.123` value for a single IP address, as well as `123.123.0.0/24` for a range of IP addresses.

The back-end implementation would need to be updated to know the difference and then confirm the current IP address accordingly.