Updated instructions for better modularity, improved starter files, and hosted-lab updates

In this release, the instructions include direct links to download the necessary files to complete the labs, including starter and solution files.

• The starter and solution files have been renamed to be more specific.
• Files no longer have sensitivity label notifications.
• Instructions updated for changes, with minor formatting and flow changes for consistency.
• Instructions have also been updated to identify how to proceed if users aren't able to access Power BI service to complete some labs.
• Updated AllfilesDownload.zip file

For users with access to hosted labs, changes include:

• Power BI Desktop updated to June 2024 version.
• VM OS updated to Windows 11.

If any issues arise, please open an issue and provide details.

Structural update to repo folders

This update allows us to move demos to GitHub repo for better maintainability. The only changes that will affect your existing experience is that there's a new folder inside of "Instructions" called "Labs" that will now hold all lab instructions. Demos folder also is in Instructions, but as it's a net-new addition.