Remove AXFR database which is dead (#1036)

Fix #1016

README.md

@@ -660,7 +660,6 @@ API | Description | Auth | HTTPS | CORS |
 ### Security
 API | Description | Auth | HTTPS | CORS |
 |---|---|---|---|---|
-| [AXFR Database](http://api.axfrcheck.com) | AXFR public database | No | No | Unknown |
 | [FilterLists](https://filterlists.com/api) | Lists of filters for adblockers and firewalls | No | Yes | Unknown |
 | [HaveIBeenPwned](https://haveibeenpwned.com/API/v2) | Passwords which have previously been exposed in data breaches | No | Yes | Unknown |
 | [National Vulnerability Database](https://nvd.nist.gov/vuln/Data-Feeds/JSON-feed-changelog) | U.S. National Vulnerability Database | No | Yes | Unknown |