Getting Started Article Revamp

[yordan-mitev]

This PR updates the main Getting Started article (Composition API + JS). The main changes are:

1. Significantly reduce the length and complexity of the article by removing the Window and DropDownList.
   • Shorter and easier-to-follow Getting Started articles reduce evaluation time and the bounce rate.
   • Less complex tutorials reduce the dropout caused by minor user errors.
   • Users are more likely to complete a shorter tutorial than a long and complex one.
2. Remove sections that promote related Kendo/Telerik products but according to Google Analytics aren't popular among page visitors (ThemeBuilder, UI Kits, etc.) and add unnecessary length.
3. Convert the Licensing section to a note and an additional link in the Next Steps section. This way we reduce the length of the article by removing a section that doesn't provide detailed step-by-step instructions and hence doesn't fit into the tutorial.
4. Comment out the yarn code snippets. These snippets must be enabled once the new docs/demos platform is available as it will support tabbed code snippets. Currently, they add unnecessary length to the article.

Outstanding tasks:

• Update the code snippets in the following sections:
  • Add a Vue Data Grid Component
  • Configure the Vue Data Grid
• Add a new Stackblitz example that reflects the updated content of the tutorial.
• Add the updated code to the github repo (if required).