add LLM evaluator example

- runs on iOS and macOS
- downloads a model / tokenizer from hugging face
- evaluates the given prompt

Applications/LLMEval/LLMEval.entitlements

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>com.apple.developer.kernel.increased-memory-limit</key>
+	<true/>
+	<key>com.apple.security.app-sandbox</key>
+	<true/>
+	<key>com.apple.security.device.usb</key>
+	<true/>
+	<key>com.apple.security.files.user-selected.read-only</key>
+	<true/>
+	<key>com.apple.security.network.client</key>
+	<true/>
+</dict>
+</plist>