Change dashboard.blade.php to use bootstrap

[elyday]

I have updated some stub files to provide a dashboard.blade.php with bootstrap support.

For the file app.blade.php I used the following examples from Bootstrap:

• Stick Footer (https://getbootstrap.com/docs/5.1/examples/sticky-footer/)
• Navbars (https://getbootstrap.com/docs/5.1/examples/navbars/)
• Jumbotron (https://getbootstrap.com/docs/5.1/examples/jumbotron/)
• Headers (the last one to use it as a "sub"-header from the nav to display the name of site ("dashboard") (https://getbootstrap.com/docs/5.1/examples/headers/)