Add ASN to logtail, collector, aggregator, frontend and CLI

proto/logtail.proto

@@ -34,6 +34,8 @@ message Filter {
   optional string website_regex      = 6;  // RE2 regex matched against website
   optional string uri_regex          = 7;  // RE2 regex matched against http_request_uri
   TorFilter       tor                = 8;  // restrict to TOR / non-TOR clients
+  optional int32  asn_number         = 9;  // filter by client ASN
+  StatusOp        asn_op             = 10; // operator for asn_number; ignored when unset
 }
 
 enum GroupBy {
@@ -41,6 +43,7 @@ enum GroupBy {
   CLIENT_PREFIX = 1;
   REQUEST_URI  = 2;
   HTTP_RESPONSE = 3;
+  ASN_NUMBER   = 4;
 }
 
 enum Window {