Add Network Adapter Configuration Tool and Presets Management

- Created NetworkAdapter.psm1 module for managing network adapters.
- Implemented functions for displaying adapter information, setting DHCP/manual configurations, and managing DNS settings.
- Added functionality to save and load network presets in JSON format.
- Introduced a schema for validating the presets structure.
- Added a .gitignore file to exclude local network presets from version control.
- Created a test-syntax.ps1 script to validate PowerShell syntax for the main script files.

test-syntax.ps1

@@ -0,0 +1,12 @@
+$files = @('NetworkAdapter.psm1','Set-NetworkAdapter.ps1')
+foreach ($f in $files) {
+    Write-Host '---' $f '---'
+    $errors = $null
+    [void][System.Management.Automation.Language.Parser]::ParseFile((Join-Path $PSScriptRoot $f), [ref]$null, [ref]$errors)
+    if ($errors -and $errors.Count -gt 0) {
+        $errors | ForEach-Object { Write-Host ("Line {0}: {1}" -f $_.Extent.StartLineNumber, $_.Message) -ForegroundColor Red }
+    }
+    else {
+        Write-Host 'No syntax errors.' -ForegroundColor Green
+    }
+}