Allow users to whitelist domains instead of just static IP addresses.

When trying to setup integrations with Bitbucket Cloud, some services face the following issues:

1. Have the IP address hard block for security reasons (DDoS) (not possible to whitelist the IP addresses).
2. The services do not have a static IP or their documentation is outdated, not being possible to whitelist all their IP addresses.

It would be great if domain whitelisting can be used as an alternative in this scenario as it would help customers that are using services like:

1. Jenkins
2. AWS
3. Azure