Add README of text generation example

This patch adds README of text generation tizen web example.

Signed-off-by: Yelin Jeong <[email protected]>

Author: niley7464

Tizen.web/TextGenerationLlama2/README.md

@@ -0,0 +1,19 @@
+# Text Generation Sample App
+## Description
+* This is a sample application of Tizen ML offloading.
+* If you want to run it on your device, Tizen 8.0 or higher is required.
+* `appsrc` and `tensor_query_client` element are used.
+
+## How to build and run
+```sh
+$ tizen build-web -- WebApplication
+$ tizen package -t wgt -- WebApplication/.buildResult/
+$ tizen build-native -a arm -c llvm -C Debug -- NsdService/
+$ tizen package -t tpk  -- NsdService/Debug/
+$ tizen package -t wgt -r NsdService/Debug/lfebC6UrMY.nsdservice-1.0.0-arm.tpk   -- WebApplication/.buildResult/Llama2.wgt
+$ tizen install -n WebApplication/.buildResult/Llama2.wgt -t rpi4
+$ tizen run -p lfebC6UrMY -t rpi4
+```
+
+## Demo
+![Alt demo](./text_generation.png)