[Build script] Polish powertoys build script (#40727)

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fix/what does it change/how was it tested (even manually, if necessary)?
-->
## Summary of the Pull Request
1. Add build parameters to build multiple types of installer
2. Add functionality to local cert management, to be able to export a
cert locally, so that the installer can be installed to other machine
3. Now the script does not need to be executed in root folder of
powertoys repo.


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## PR Checklist

- [ ] **Closes:** #xxx
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [X] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

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or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

<!-- Describe how you validated the behavior. Add automated tests
wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed
I build an installer locally, and verified packaged apps(New+,
powerRename, cmdpal/) etc can be installed successfully. And powertoys
can be installed without problem

tools/build/cert-management.ps1

@@ -152,4 +152,37 @@ function Export-CertificateFiles {
     if (-not $CerPath -and -not $PfxPath) {
         Write-Warning "No output path specified. Nothing was exported."
     }
+}
+
+# Main execution when script is run directly
+if ($MyInvocation.InvocationName -ne '.') {
+    Write-Host "=== PowerToys Certificate Management ===" -ForegroundColor Green
+    Write-Host ""
+    
+    # Ensure certificate exists and is trusted
+    Write-Host "Checking for existing certificate or creating new one..." -ForegroundColor Yellow
+    $cert = EnsureCertificate
+    
+    if ($cert) {
+        # Export the certificate to a .cer file
+        $exportPath = Join-Path (Get-Location) "PowerToys-CodeSigning.cer"
+        Write-Host ""
+        Write-Host "Exporting certificate..." -ForegroundColor Yellow
+        Export-CertificateFiles -Certificate $cert -CerPath $exportPath
+        
+        Write-Host ""
+        Write-Host "=== IMPORTANT NOTES ===" -ForegroundColor Red
+        Write-Host "The certificate has been exported to: $exportPath" -ForegroundColor White
+        Write-Host ""
+        Write-Host "To use this certificate for code signing, you need to:" -ForegroundColor Yellow
+        Write-Host "1. Import this certificate into 'Trusted People' store" -ForegroundColor White
+        Write-Host "2. Import this certificate into 'Trusted Root Certification Authorities' store" -ForegroundColor White
+        Write-Host "Certificate Details:" -ForegroundColor Green
+        Write-Host "Subject: $($cert.Subject)" -ForegroundColor White
+        Write-Host "Thumbprint: $($cert.Thumbprint)" -ForegroundColor White
+        Write-Host "Valid Until: $($cert.NotAfter)" -ForegroundColor White
+    } else {
+        Write-Error "Failed to create or find certificate. Please check the error messages above."
+        exit 1
+    }
 }