Refactor Permalinks box

Following !1312 (closed), I'm opening this smaller MR regarding Permalinks box refactoring. It includes:

• UI rearrangement
• New copied feedback on buttons
• Guided tour update

In the end, I have chosen to add the copied feedback directly on buttons instead of a popover (see screenshots below). Indeed, I could not make bootstrap tooltip/popover work with the regular tooltip on buttons. Bootstrap themselves did a very ugly hack to make something work, that they advise against (https://github.com/twbs/bootstrap/blob/e3e00b5002139adb0d5dadd6002e15b7b6cd371f/site/assets/js/partials/code-examples.js#L67). So this solution seemed to me the most elegant one and well integrated into the current UI.

Screenshots:

Before:

After: