Standardize ASP filenames: remove underscores

Renamed 45 ASP files to follow lowercase concatenated naming convention:
- Direct handlers: save_machine_direct.asp -> savemachinedirect.asp
- USB files: checkin_usb.asp -> checkinusb.asp
- API files: api_usb.asp -> apiusb.asp
- Map files: network_map.asp -> networkmap.asp
- Printer files: printer_lookup.asp -> printerlookup.asp

Also:
- Updated 84+ internal references across all ASP and JS files
- Deleted 6 test/duplicate files (editmacine.asp, test_*.asp)
- Updated production migration guide with filename changes
- Added rename scripts for Linux (bash) and Windows (PowerShell)

addsubnet.asp

@@ -46,7 +46,7 @@
                   </thead>
                   <tbody>
                     <tr>
-		      <form method="post" action="./addsubnetbackend_direct.asp">
+		      <form method="post" action="./addsubnetbackenddirect.asp">
                       <th scope="row"><input class="form-control" type="text" name="vlan" size="4"></th>
                       <td><select name="subnettypeid"  class="btn btn-light px-3">
 <%