Migrate to UIkit v3

[arvindpdmn]

This is lot of work since Joomla template will need changes. Just recording useful links for future reference. UIkit v3 has better support for hover tooltips on touchscreens.

• https://getuikit.com/docs/migration
• https://developer.mozilla.org/en-US/docs/Web/CSS/@media/hover
• https://medium.com/@mezoistvan/finally-a-css-only-solution-to-hover-on-touchscreens-c498af39c31c
• Add bookmark and run on page: javascript: (function () { var script = document.createElement('script'); script.setAttribute('src', 'https://getuikit.com/migrate.min.js'); document.body.appendChild(script); }());

In .htaccess, unsafe-eval can be removed if upgraded to v3. See uikit/uikit#3115

[arvindpdmn]

Reevaluate due to #579