[Tools] Adding snippet generator and update script

The focus of these changes is to add the snippet
generator tool from the Azure development feed
and a PowerShell script to update snippets.

Author: jsquire

.config/dotnet-tools.json

@@ -0,0 +1,13 @@
+{
+  "version": 1,
+  "isRoot": true,
+  "tools": {
+    "Azure.Sdk.Tools.SnippetGenerator": {
+      "version": "1.0.0-dev.20241213.1",
+      "commands": [
+        "snippet-generator"
+      ],
+      "rollForward": false
+    }
+  }
+}

nuget.config

@@ -4,5 +4,6 @@
     <!--To inherit the global NuGet package sources remove the <clear/> line below -->
     <clear />
     <add key="nuget" value="https://api.nuget.org/v3/index.json" />
+    <add key="azure-sdk-dev-feed" value="https://pkgs.dev.azure.com/azure-sdk/public/_packaging/azure-sdk-for-net/nuget/v3/index.json" />
   </packageSources>
 </configuration>

scripts/Update-Snippets.ps1

@@ -0,0 +1,24 @@
+[CmdletBinding()]
+param(
+    [string]$Path
+)
+
+# If this is not a real path, assume snippets should be refreshed in a relative
+# path to the OpenAI.csproj file from the git root.
+if (-not $Path) {
+    $_gitRoot = git rev-parse --show-toplevel 2>$null
+
+    if ((-not $_gitRoot) -or ($LASTEXITCODE -ne 0)) {
+        Write-Error "Could not determine the git root directory. Please specify the path to the project file."
+        exit 1
+    }
+
+    $Path = Join-Path -Path $_gitRoot -ChildPath '/src/OpenAI.csproj'
+    $Path = (Resolve-Path -LiteralPath $Path).Path
+}
+
+# Update snippets
+Write-Host "Updating snippets in $Path"
+
+dotnet tool restore
+dotnet tool run snippet-generator -b $Path $additionalArgs