feat(config-api): Blacklist some urls from webhook for security reason

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### Description

Currently there is no security in webhook feature.
The following should be check:

1. Perform URL validation(url should be valid url and resolvable).
1. Ensure URL starts with "https://", disallow "file://" and other non-HTTPS schemes.
1. Block typical local IPs: 127.0.x, 192.168.x, 172.x.
1. Prohibit "localhost" and "http://"
1. Require a specific response header for POST requests, unique to the customer.