Standardize UI consistency across ShopDB pages

Security fixes:
- Add HTMLEncode to displaysubnets.asp output
- Add HTMLEncode to displayapplications.asp URL attributes

Icon standardization:
- Use zmdi-plus-circle for all Add buttons (displaypcs, pcs, pclist, computers, listpcs)
- Use zmdi-edit for all Edit tab icons (displayapplication, displayprinter, displaysubnet, displaydevice)
- Replace icon-note with zmdi icons throughout

Layout consistency:
- Standardize title row margin-bottom to 15px across all pages
- Add table-hover class to all data tables
- Fix editpc.asp title from "Edit Equipment" to "Edit PC"
- Fix editpc.asp back link to point to displaypcs.asp

Terminology:
- Change "Make" to "Vendor" in displayprinters.asp
- Standardize Back button text to "Back to [Page]" format

Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

addprinter.asp

@@ -36,7 +36,7 @@
                   <i class="zmdi zmdi-print"></i> Add Printer
                 </h5>
                 <a href="./displayprinters.asp" class="btn btn-sm btn-secondary">
-                  <i class="zmdi zmdi-arrow-left"></i> Back
+                  <i class="zmdi zmdi-arrow-left"></i> Back to Printers
                 </a>
               </div>