Update IP Allow List to Support Range

[WillStrohl]

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.

[davidjrh]

By this documentation https://docs.microsoft.com/en-us/azure/devops/organizations/security/allow-list-ip-url?view=azure-devops#ip-addresses-and-range-restrictions, current IP Address ranges for outbound connections coming from Azure Pipelines hosted agents in CIDR notation are:

13.107.6.0/24
13.107.9.0/24
13.107.42.0/24
13.107.43.0/24