Adjusted validation regex

To relax AMP domain validation, the validation regex was adjusted to allow for adding domains like amp.localhost, amp.sub.domain.com or amp.com/kentico (to support virtual directories). The new regex is taken from https://mathiasbynens.be/demo/url-regex, specifically the one from @diegoperini, as it has the best results in validation.

CMS/App_Data/CIRepository/@global/cms.settingskey/ampfilterdomainalias.xml

@@ -17,7 +17,7 @@
   <KeyOrder>2</KeyOrder>
   <KeyType>string</KeyType>
   <KeyValidation>
-    <![CDATA[^(?!.{256})(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?\.)+(?:[a-z]{1,63}| xn--[a-z0-9]{1,59})$|localhost(:[\d]+)?|127.0.0.1(:[\d]+)?]]>
+    <_^(?:(?:https?|ftp)://)(?:\S+(?::\S*)?@)?(?:(?!10(?:\.\d{1,3}){3})(?!127(?:\.\d{1,3}){3})(?!169\.254(?:\.\d{1,3}){2})(?!192\.168(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\x{00a1}-\x{ffff}0-9]+-?)*[a-z\x{00a1}-\x{ffff}0-9]+)(?:\.(?:[a-z\x{00a1}-\x{ffff}0-9]+-?)*[a-z\x{00a1}-\x{ffff}0-9]+)*(?:\.(?:[a-z\x{00a1}-\x{ffff}]{2,})))(?::\d{2,5})?(?:/[^\s]*)?$_iuS>
   </KeyValidation>
   <KeyValue>amp.domain.com</KeyValue>
-</cms.settingskey>
+</cms.settingskey>