Fix Modal positioning

Modal positioning is affected by its parent elements, so to make it render correctly, vue-simple-portal moves rendered modal html to the bottom of the page.

Author: obulat

package-lock.json

@@ -25,6 +25,7 @@
         "@fortawesome/free-brands-svg-icons": "^5.12.0",
         "@fortawesome/free-solid-svg-icons": "^5.12.0",
         "@fortawesome/vue-fontawesome": "^0.1.9",
+        "@linusborg/vue-simple-portal": "^0.1.4",
         "@sentry/browser": "^5.12.5",
         "@sentry/integrations": "^5.12.5",
         "buefy": "^0.8.8",