Add info tooltip

Add a new component which uses tippy and a circle-info icon for showing simple information tooltips.

packages/tooltip/src/tooltip.js

@@ -33,6 +33,7 @@ export class TooltipElement extends ScopedElementsMixin(DBPLitElement) {
 
         tippy(this._('#tooltip-icon'), {
             content: this.textContent,
+            appendTo: this.shadowRoot,
         });
     }