10389 react tooltip components (#10473)

* poc: Use react-popper for tooltips #10389

* poc: Add popover component and use a hoc() for Tooltip + Popover to avoid code duplication #10389

* jest: Add snapshot tests to Popover and Tooltip #10389

* poc: Move target from hoc into Popover/Tooltip-component #10389

* poc: Clean up unused styles and use the existing Grafana style/colors on popper tooltip #10389

* poc: Remove test code before PR

* poc: Remove imports used in poc but shouldn't be included anymore #10389

package.json

@@ -149,6 +149,7 @@
     "react": "^16.2.0",
     "react-dom": "^16.2.0",
     "react-grid-layout": "^0.16.1",
+    "react-popper": "^0.7.5",
     "react-sizeme": "^2.3.6",
     "remarkable": "^1.7.1",
     "rxjs": "^5.4.3",