Add a llms.txt to provide basic links to dash.js related information … (Dash-Industry-Forum#4846)

* Add a llms.txt to provide basic links to dash.js related information for LLMs

* Minor edits to llms.txt

Author: dsilhavy

llms.txt

@@ -0,0 +1,19 @@
+# dash.js
+
+> dash.js is a reference client implementation for the playback of MPEG DASH via JavaScript in browser based environments that support the Media Source Extensions and optionally the Encrypted Media Extensions.
+
+## Docs
+
+- [dash.js Quickstart](https://dashif.org/dash.js/pages/quickstart): A brief overview on how to use dash.js
+- [Installation Instructions](https://dashif.org/dash.js/pages/quickstart/installation.html): Instructions on how to obtain the dash.js bundles
+- [Setup Guide](https://dashif.org/dash.js/pages/quickstart/setup.html): An overview on how to setup dash.js in your application
+- [Usage Guide](https://dashif.org/dash.js/pages/usage/): Various examples on how to use specific features of dash.js
+
+## API
+
+- [API List](https://cdn.dashjs.org/latest/jsdoc/index.html): A complete API reference for dash.js
+
+## Examples
+
+- [Sample Section](https://reference.dashif.org/dash.js/nightly/samples/index.html): Various samples demonstrating dash.js features
+