Copy docs into Zeek repo directly

This is based on commit 2731def9159247e6da8a3191783c89683363689c from the
zeek-docs repo.

doc/scripting/data_struct_set_declaration.zeek

@@ -0,0 +1,22 @@
+event zeek_init()
+    {
+    local ssl_ports: set[port];
+    local non_ssl_ports = set( 23/tcp, 80/tcp, 143/tcp, 25/tcp );
+    
+    # SSH
+    add ssl_ports[22/tcp];
+    # HTTPS
+    add ssl_ports[443/tcp];
+    # IMAPS
+    add ssl_ports[993/tcp];
+    
+    # Check for SMTPS 
+    if ( 587/tcp !in ssl_ports )
+        add ssl_ports[587/tcp];
+    
+    for ( i in ssl_ports )
+        print fmt("SSL Port: %s", i);
+
+    for ( i in non_ssl_ports )
+        print fmt("Non-SSL Port: %s", i);
+    }